Quality Control 101: What Is Specific Gravity?

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So far, in our quality control series, we’ve discussed Mohs hardness and absorption—but there are still many other factors that play a role in creating specialty aggregates, natural thin stone veneer, and other products that will last. Today, we’re diving into the importance of specific gravity and bulk specific gravity in stone. Let’s take a look at what this physical property can tell us, why it’s so important, and how it’s measured.

What Is Specific Gravity?

Specific gravity is a ratio of the mass of a substance to the mass of the same volume of liquid (typically distilled water). This physical property plays an important role across a wide range of processes, from biological processes like kidney function to product performance. 

You may have also heard this property referred to as “relative density.” The word “relative” should hint at the fact that specific gravity is a unitless measurement. To make sense of this property, measurements must be compared against a standard. For solids and liquids, that standard is water at its most dense (about 39 degrees Fahrenheit), while gases are measured against room temperature air.

As water is the typical standard, it is understood to have a specific gravity of 1. A specific gravity below 1 indicates that a substance is less dense than water and will therefore float in the liquid, while a specific gravity greater than 1 means that the substance is more dense and will sink. Specific gravity in natural stone ranges from 2 to 3, meaning that stone is two to three times denser than water.  

Water Absorption and Bulk Specific Gravity in Stone

Specific gravity doesn’t exist in a vacuum, however; when it comes to the performance of natural stone products, other physical properties must be accounted for. Water absorption and specific gravity are two properties that go hand in hand.

All types of natural stone are porous to some degree, meaning that they will absorb a certain amount of water. Absorption allows us to assess that porosity, which in turn allows us to evaluate how well a stone will withstand weathering and structural stress. In general, denser stone is less porous. Because water absorption is measured as a percent by weight, however, a low-density and high-density stone can have the same absorption capacity—but the higher-density stone will actually absorb more water by volume. 

To allow for this caveat, we measure bulk specific gravity. This property takes into account a stone’s absorption capacity, giving us a better understanding of how strong the resulting product will be, how it might be affected by the freeze-thaw cycle and other natural forces, and what it can realistically be used for.

Specific Gravity and Quality Control

So, how does specific gravity in stone relate back to quality control? When it comes to natural stone products, consistency is key. Specialty aggregates used in architectural precast, decorative precast, and other manufactured products need to meet specifications for a particular application or installation. At Kafka Granite, we make key measurements like Mohs hardness, specific gravity, and absorption available directly to our customers, so that they can make the most informed decisions when sourcing materials for their projects.

Even non-load bearing products like natural thin stone veneer have to hold up to the installation process, the elements (if exterior), and forces like heat and changes in humidity. This means that every masonry unit needs to fit into an acceptable range of physical properties, from Mohs hardness to bulk specific gravity. 

How Is Specific Gravity in Stone Tested?

It’s not enough to simply be aware of standards—those standards need to be met every time. Kafka Granite adheres to ASTM material specifications for our stone products. Samples of our dimension stone are sent out for a number of tests, including ASTM C97: Standard Test Methods for Absorption and Bulk Specific Gravity of Dimension Stone. This particular assessment is used to measure both absorption capacity and bulk specific gravity for all types of dimension stone except slate. 

Absorption is up first. At least five test specimens are dried for 48 hours in an oven to ensure they’re completely free of moisture. Their dry weight is recorded, and they are then submerged in water for another 48 hours to make sure they’ve naturally reached their absorption capacity. When fully saturated, the samples are weighed again. The percentage difference between these two values is the absorption capacity.

To determine bulk specific gravity, the saturated specimen is suspended by a wire in air and weighed. The process is repeated with the stone suspended in water. The difference between these two values is the bulk specific gravity, which can then be used to determine density.

The testing process is similar for our specialty aggregates, but it’s important to note that, unlike dimension stone, aggregate or crushed stone isn’t required to conform to any one standard. However, this data determines whether crushed stone is appropriate for a specific application—so it still needs to be collected. Samples of our specialty aggregates are subjected to a similar process of drying, soaking, and weighing to determine both their absorption and specific gravity.

Kafka Granite’s Commitment to Excellence in Stone Products

Our decades of experience in the industry have made it clear to us that architects, designers, stonemasons, and others need high-quality specialty aggregates and masonry units that will hold up under stress and against natural forces. At Kafka Granite, we’re committed to providing consistent, useful products that fit perfectly into a project. If you’re searching for thin stone veneer or other natural stone products, reach out today. We’re always happy to answer any questions you may have.

Quality Control 101: What Is Absorption?

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Here at Kafka Granite, we’re dedicated to providing high-quality stone products—but that’s not the only thing that makes us an industry leader. Our dedicated team is constantly seeking out colorful new deposits and developing innovative uses for natural stone and products to meet the ongoing needs of our customers. We’re also happy to share our technical knowledge. To that end, we’re diving into the next topic in our quality control series: absorption. 

In previous installments, we’ve talked about the overall importance of quality control, dug a little deeper into Mohs hardness, and specific gravity. Now, we’ll be looking at what absorption is, how it’s measured, and why it matters to the end-user.

Why Does Absorption Matter?

Absorption is the percent by weight increase in the mass of a material when water is absorbed into its pores. (This does not include any water adhering to the surface of the material.) This acts as a measure of a stone’s porosity, which can tell us quite a lot about how durable that stone will be for a particular installation.

If you’re wondering exactly why water absorption matters in natural stone products, know that it all comes back to quality control. Different absorption levels determine how well a specific type of stone will withstand weathering and structural stress, and, by extension, how a product can be used. It’s essential that the qualities of a stone match the needs of the application; otherwise, your project simply won’t last.

Absorption capacity is particularly important in natural stone products that will be exposed to the elements and undergo the freeze-thaw cycle. If you’re creating a building facade from natural stone, for example, you’ll need to select an appropriate type of stone—one that is durable and not overly porous. If your material absorbs too much water, you’ll find it much more vulnerable to freezing weather. 

As another example, if you’re sourcing decorative aggregates for the face mix of your pavers, you should opt for an aggregate mix with a lower absorption. Continued freeze-thaw cycles and other forces will make aggregates with higher absorption levels more likely to break down over time, eventually compromising the integrity of the paver itself.

Finally, absorption can also tell us about a stone’s stain resistance. To protect the integrity of your installation and reduce the risk of your material becoming stained over time, it’s essential to choose a stone with a low water absorption.

How Do You Test for Water Absorption of Stone?

Water Absorption of Dimension Stone

Dimensional stone sold for commercial use must meet certain criteria across a number of categories, including absorption, specific gravity, and compressive strength.

ASTM International is a non-profit organization that develops both material standards and testing methods for products and materials throughout numerous industries. ASTM C97: Standard Test Methods for Absorption and Bulk Specific Gravity of Dimension Stone is used to test absorption capacity for a variety of types of dimension stone, such as marble and granite. 

Here’s a brief look at how the test progresses:

  • Five or more test specimens are prepared.
  • The samples are dried in an oven for 48 hours to ensure they are completely free of excess moisture. 
  • When totally dry, the specimens are weighed.
  • Next, the samples are submerged in water for another 48 hours to make sure they’ve naturally reached their absorption capacity.
  • When completely saturated, the samples are weighed again.

The absorption capacity of each sample is determined by calculating the difference between the fully dry and fully saturated weights. The resulting value, expressed as a percentage, gives us one piece of the puzzle for determining whether a type of stone is appropriate for a specific application.

Along with testing methods, there are ASTM specifications to which natural stone products must adhere. The standard requirement for water absorption in granite, for example, is .4 percent, while marble is .2 percent. 

It’s important to note that the absorption capacity of each type of dimension stone is actually a range, rather than one number. Absorption capacity in granite typically ranges from .8 to .01 percent, while marble goes from .8 to .04 percent. This means that a portion of natural stone sold on the market will fall outside of ASTM specifications. 

This brings us back to the essential nature of quality control. Remember that the most affordable option may not be the best option for your project—in fact, specifying low-quality natural stone products may actually end up costing you more in repairs and replacements in the long run. If you ever find yourself in doubt, be sure to ask your supplier for proof of ASTM testing.

Water Absorption of Crushed Stone

Our crushed stone is also regularly tested for absorption, Mohs Hardness, and specific gravity. But unlike dimension stone, there is no universal standard for water absorption of aggregate or crushed stone. Instead, organizations or businesses typically have specifications for materials they use in different projects. The Wisconsin Department of Transportation, for example, has a set standard for epoxy overlay aggregates. It’s essential that materials used in projects like high-friction surfacing installation meet these specifications. Otherwise, the aggregate will break down—reducing traction and failing to perform. 

To ensure that an aggregate meets the requirements for a particular application, samples are tested according to ASTM standards, such as ASTM C127: Standard Test Method for Relative Density (Specific Gravity) and Absorption of Coarse Aggregate. 

The method for testing water absorption in aggregate or crushed stone is similar to that of dimension stone:

  • Aggregate samples are first dried to remove any excess moisture.
  • Once dry, the oven-dry density of the aggregate is measured.
  • Next, the samples are soaked in water for a prescribed period to ensure that they reach maximum absorption capacity.
  • Finally, the soaked samples are used to determine the saturated-surface-dry density and absorption.

High-Quality Stone Products From Kafka Granite

When you purchase specialty aggregates or other natural stone products from Kafka Granite, you can rest easy knowing the materials you receive will be of the highest quality. To further demonstrate our commitment to transparency and quality, all test data is available to our customers upon request.

We pride ourselves on our attention to detail and continuous pursuit of excellence—and we’re always happy to discuss your newest project. If you have any questions about our range of products or specifications, feel free to contact us today.

Beige Blend Stabilized Pathway Mix - North Coast Harbor - Cleveland, OH

How to Maintain a Stabilized Pathway

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Preventative upkeep and regular maintenance will go a long way towards keeping your pathways in good shape. But what are the specific steps you should be taking, and how do you fix a pathway once it’s been damaged? We’ve got the answers.

Kafka Granite’s Stabilized Pathway Mix is a combination of decomposed granite or crushed stone screenings blended with a stabilizing binder. Not only does it offer a natural, effortless look, but it also resists erosion and holds up well under traffic. But like all other outdoor installations, a stabilized pathway requires routine maintenance. Here’s a quick guide to keeping yours looking pristine.

Maintaining Your Stabilized Pathway

For Organic-Lock™ blended aggregates, we recommend doing a thorough analysis one week after installation, followed by monthly evaluations. These regular checks will allow you to identify damage and potential problem areas before they get out of hand.

Erosion

Erosion (usually from rainfall) is one of the most significant causes of damage. Fortunately, the stabilizing binders used in Kafka Granite’s mix allow pathways to resist erosion and hold up significantly better under heavy traffic than a standard or non-stabilized mix. If you do notice erosion damage to your pathway, the best course of action will be to figure out where the water is coming from and then divert it around the pathway. This can be accomplished by installing features such as drains, culverts, and diverters. Once you’ve successfully dealt with the source of the water issue, you can go about replacing any lost material.

Excess Loose Material

While Stabilized Pathways are designed to have some loose material on top, you may find that overtime the installation has more loose material than desired. As your stabilized pathway is exposed to foot traffic, the elements, and the passage of time, pieces of aggregate will eventually loosen on the surface of the installation. If the depth of these particles exceeds ¼ inch, it’s time to either sweep or shovel and remove them. Depending on how much material is removed, it may be recommended to replenish your pathway with new material.

Debris

In addition to excess loose material, debris will likely build up on your pathway. Depending on the location of the installation, that might include soil, gravel, grass clippings, or other organic material. You can remove debris from your stabilized pathway by hand raking or mechanically blowing the area.

Snow

If your stabilized pathway will be exposed to snow at any point during the year, it’s essential to understand how to properly plow it. The blade of the plow will need to be lifted ¼ inch off the surface of the pathway, which can be accomplished with either a shoe lift or rubber baffle. This small amount of space will allow you to plow snow without damaging the pathway beneath it.

Mixing Patch Material for a Stabilized Pathway

Even stabilized pathways that are diligently cared for may eventually require new material. We recommend keeping a small amount of the Organic-Lock blended aggregate on hand as attic stock. When the time comes to patch an area, you’ll have all the supplies you need to address the issue quickly and efficiently.

The Snowball or Step Test

Ideally, your mixture should reach a moisture content of 8-10%, which you can assess using the following techniques. If you can easily form a snowball-shaped handful with your material, it’s ready to go. But if it crumbles or has a wet sheen to it, you’ll need to add more water or more dry material. You can also test your mixture’s readiness by forming a rough ball and stepping on it. You should see a perfect impression of your bootprint, without any crumbling or noticeable wet sheen.

Too Wet

Too Dry

Just Right

Left foot print: too wet | Right foot print: ideal

Fixing Slightly Damaged Areas

If the pathway material below the loose surface particles is damaged, it will need to be fixed—because it can no longer stand up to erosion or traffic. Light damage can be reversed without excavating the area: simply soak the site, scarify with a rake to 1-2 inches, and then use a hand tamper or roller to compact the area.

Fixing Severe Damage to a Stabilized Pathway

Severe damage to your stabilized pathway will require a more in-depth fix. First, excavate the area to a depth of 2 inches to approximately a 50% increase in surface area. Evaluate and add an appropriate amount of stabilized pathway mix to the area. Finally, you’ll need to blend the new mix into the existing site. You have two options for this step:

  • Using multiple passes, rototill to a depth of 2 inches. Take care not to exceed the depth of the blended aggregate. To blend the existing and new material, spray the surface of the area lightly and begin to till. If needed, add water until you achieve the correct moisture content.
  • Remove the existing material and blend in new material on a clean pad. Depending on the size of your installation, you may use either a shovel or a front end loader to turn the material until you’ve created a homogenous blend. Finally, spread your mixture back over the excavated area, and add water until your mixture reaches its ideal consistency.

Pathway Mixes From Kafka Granite

When properly cared for, your stabilized pathway can last for years to come, offering a beautiful and functional route for public or private use. Kafka Granite is proud to provide the products and expert knowledge you need to make a project successful and maintain its integrity over time. If you have any questions about maintaining a stabilized pathway, don’t hesitate to contact us.

Moh's Hardness Test Example

What Is Mohs Hardness?

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We’ve touched on the importance of quality control in stone products before—after all, consistency is critical throughout the process of manufacturing precast concrete aggregates and other specialty natural stone materials. Today, we’re diving even deeper into one of the factors that contribute to a stone’s inherent quality: Mohs hardness. Here’s some information on the history of the measurement and exactly what it means for consumers. 

A Quick History of Mohs Hardness

We have Friedrich Mohs, a German mineralogist, to thank for the Mohs scale of mineral hardness. This essential scale is used to measure the scratch resistance of a material like quartz or granite. Possible measurements range from 1 to 10, with 1 indicating the softest material and 10 the hardest.

Mohs created his scale in 1812 as a way to identify specific minerals. By scratching a specimen with one of ten reference minerals, a person could identify the relative hardness and, potentially, the exact type of mineral they were dealing with. Geologists in the field continue to use this method for identifying minerals. At times, hardness picks are used in place of reference minerals. In a pinch, ordinary objects like glass, a knife blade, or even your fingernail can be used to determine the relative hardness of a mineral. 

How Does Mohs Hardness Affect the End User?

The Mohs hardness scale is particularly important to Kafka Granite’s industrial customers, such as manufacturers of terrazzo flooring. Depending on what the aggregate is being used for, there may be an industry specification or product standard that states how hard the stone needs to be.

Continuing with our terrazzo example, those applications typically call for a softer stone, because it polishes easier. Marble is one excellent option here. On the other hand, manufacturers of architectural precast wall panels or decorative concrete pavers usually prefer to use aggregate made from one of the harder stones, because they are more abrasive—and they’re looking for an exposed aggregate finish that will last a lifetime. 

This abrasive quality allows harder stone products to stand up to harsh environments. Since terrazzo flooring is typically found indoors, it does not face the same elements of freeze/thaw, snow removal, and vehicular traffic that epoxy overlay streetscapes may be exposed to. Exposure to both natural elements and human traffic can play a significant role in the breakdown of a material.

Mohs Hardness and Construction Specifications

Before embarking on a project, manufacturers need to know that their chosen material meets certain industry standards or requirements. Depending on the product being manufactured, such as high-friction surfacing, there may be stringent specifications that need to be hit—both to ensure the integrity of an aggregate and the longevity of the finished product.

Take epoxy overlay aggregates, for example. Hardness is an extremely important quality for products made from these materials. The Department of Transportation (DOT) has a number of exact requirements for the types of stone they use in high-friction surfacing applications, including size and hardness of the aggregate. For obvious reasons, the DOT wants the stone to wear down as slowly as possible over time. A harder aggregate allows the final product, whether it be an entrance ramp or a bridge deck, to retain its integrity.

Sourcing stone that meets stringent specifications is no easy task, particularly if you’re searching for a particular color. Luckily, Kafka Granite offers a wide range of products with different levels of hardness. Whatever you have in mind, we’ll work to find a stone that matches your vision. You may only know that you need a hard, gray stone for your manufacturing project, for example. While we do have gray marble, we’re also able to supply gray granite that would better meet the needs of your project.

Mohs Hardness and Cost

Quality control in specialty aggregates is essential, but it’s not the only factor that will determine your choice of supplier. Hardness also has a direct effect on the equipment being used to process stone. More abrasive stone is harder on machinery and will eventually wear it down, while something that’s softer has less of an impact. This, in turn, affects cost—and potentially your ability to source certain materials. Marbles are more affordable to produce than quartz, for example. Ideally, industrial manufacturers will be able to work with their aggregate supplier to source material that both meets specifications and fits within their set budget.

High-Quality Aggregates for Your Next Building Project

Kafka Granite is proud to be one of the largest manufacturers and suppliers of specialty aggregates in the country. We offer over 60 varieties of crushed marble, quartz, granite, and recycled materials. If you’re searching for a specialty aggregate for use in architectural precast concrete, pavers, terrazzo flooring, or any number of natural stone products, contact us today to learn more about how we can crush and screen aggregates to your desired specifications.

Gun Metal & Misty Gray Marble Blend - Dimensional Cut

The Possible Applications of Natural Thin Stone Veneer

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Natural stone gives both commercial and residential projects a highly sought-after, rugged look that has stood the test of time. Where trends fall out of fashion as the seasons change, natural stone sticks around. But all too often, designers and builders have to choose cheaper or more readily available options like manufactured stone for their projects.

Fortunately, natural thin stone veneer offers an attractive alternative. This versatile specialty building stone adds the same look of natural full stone veneer while lowering shipping and installation costs dramatically. This type of building stone has multiple uses and can complement a variety of interior and exterior projects—in fact, there are so many possible applications for natural stone veneer that it can be difficult to narrow down your options and determine exactly where you should use this material. 

If you’re looking for some natural stone veneer inspiration, you’ve come to the right place. Kafka Granite has spent decades sourcing natural stone from quarries across the continent. Our selection of natural thin stone veneer offers the perfect color and cut for every need, and we’re happy to help you figure out which option is right for your unique project. Here’s a look at some of the potential uses for natural thin stone veneer.

The Benefits of Utilizing Thin Stone Veneer

Thin stone veneer can range in thickness from ¾ inches to 1½ inches. This specification results in a product that weighs less than 15 pounds per square foot. Not only does this cut down significantly on shipping prices when compared to full veneer, but it also impacts installation costs. Due to its light weight, thin stone veneer doesn’t require footing or other supports, which makes the installation process simpler and often quicker than laying full veneer. 

Natural stone veneer can complement a wide variety of projects—both within a building or home and out. But while thin stone veneer is ideal for use in both commercial and residential projects, Kafka Granite does recommend hiring a professional stonemason to install this specialty product. He or she will be able to ensure that your natural stone materials are installed properly.

Applications of Natural Stone Veneer 

The sky is truly the limit when it comes to the use of natural thin stone veneer. This specialty building stone is a striking addition to any non-structural project, whether it be a restaurant building facade or an indoor waterfall. Let’s take a look at some of the many possible applications of thin stone veneer. 

Gun Metal & Misty Gray Marble Blend - Dimensional Cut

Gun Metal & Misty Gray Marble Blend – Dimensional Cut

Interior Thin Stone Veneer Projects

Natural thin stone veneer is an excellent option for incorporating the beautiful look of natural stone into an interior project. Because the product is relatively lightweight, thin stone veneer does not require special footing and can be easily installed for a variety of non-structural features, from accent walls to kitchen backsplashes. 


Interior Accent Walls

Whether you’re decking out your home in natural stone or just hoping to create a single accent wall, thin stone veneer will do the trick. Because quarried stone varies depending on its source, you’ll find a wide variety of colors available—and one is sure to match your vision.

Fireplace Projects

Indoor fireplaces can add a cozy feel to any room, depending on how they’re built and decorated. Natural stone veneer can turn a plain fireplace facade into an eye-catching centerpiece.

Gun Metal & Misty Gray Marble Blend - Dimensional Cut

Gun Metal & Misty Gray Marble Blend – Dimensional Cut

Kitchen Backsplashes

Backsplashes might not seem like an obvious choice for thin stone veneer, but they present a unique opportunity to showcase the beautiful, natural colors of these products.

Interior Accent Finishes

Perhaps you’re working within a smaller space or simply don’t want to use natural stone for an entire project. You can still incorporate the lovely look of natural stone with the help of thin stone veneer panels and other products. Our wide variety of cuts and colors makes finding the right accent for your project a breeze.

Exterior Uses for Thin Stone Veneer

Natural thin stone veneer also stands up extremely well in the outdoors. When installed with care and maintained correctly, this specialty building stone will retain its integrity and keep your project looking striking for years to come. 

But remember—if you are planning to utilize natural thin stone veneer in your exterior project, the surface area that will be in contact with the natural thin stone veneer will first need to be waterproofed before this specialty product can be installed. 

Gun Metal Marble - Dimensional Cut

Gun Metal Marble – Dimensional Cut

Exterior Siding and Columns

Natural thin stone veneer is an ideal material for exterior or partial wall siding, as well as exterior columns. The material holds up extremely well to the elements, including harsh winds, rain, and snow. Whether you’re looking to add some old-world country charm to your home or create a clean, contemporary feel for the front wall of a business, you’ll be able to find the perfect blend amongst our numerous cuts and colors.

Gun Metal & Misty Gray Marble Blend - Dimensional Cut

Gun Metal & Misty Gray Marble Blend – Dimensional Cut

Chimney Surfacing

Natural stone can look just as handsome on your exterior chimney as it can adorning your fireplace—even as time and the elements weather the product. In contrast to artificial or manufactured stone, which can fade over time, natural stone will retain its color and integrity, giving you a chimney surface or other exterior project that lasts.

Natural Stone Veneer From Kafka Granite

Over the past 40 years, Kafka Granite has distinguished itself as an industry leader in specialty aggregates, and we’re proud to extend that same level of excellence, dedication, and innovation to our specialty masonry stone products. Reach out today to speak to a knowledgeable sales representative. We look forward to helping you incorporate natural stone into your project.

Gun Metal & Misty Gray Marble Blend - Dimensional Cut

6 Things You Didn’t Know About Thin Stone Veneer

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The manufacturing process for creating thin stone veneer products has been around for some time, yet this versatile material is still a mystery to many. A few short years ago, Kafka Granite expanded our line of stone products to include thin stone veneers made from granite, quartz, and marble, in the classic Kafka colors that architects, designers, and builders have come to know and love. 

Homeowners and designers alike are now discovering and benefiting from the unique properties of natural thin stone veneer. Here are a few fast facts you may not have known about this specialty building material.

1. Thin Stone Veneer Doesn’t Require Footing

One of the most significant advantages of thin stone veneer over full veneer is that the former can be installed without support ledges or footings. Why? It all comes down to weight. At less than 15 pounds per square foot, thin stone veneer can weigh up to 75% less than full veneer building stone. This makes installation significantly easier, but it also cuts down on shipping costs dramatically. 

2. Natural Thin Stone Veneer Works for Interior and Exterior Projects

Natural thin stone veneer is prized for its versatility and durability. As we mentioned, its light weight cuts down on shipping and installation costs. And because natural stone retains its integrity as it weathers, natural thin stone veneer is an ideal choice for both interior and exterior projects. That means that anything from your kitchen backsplash to a building facade can be enhanced by the beauty of natural stone.

3. When Installed Correctly, It Looks Just Like Full Veneer Stone

Thin veneer ranges in thickness from ¾ inches to a maximum of 1½ inches. This is significantly thinner than full veneer building stone. You might wonder how this slimmer version could possibly compare to stone that is several inches thicker. In reality, thin stone veneer stands up quite nicely to its full counterpart. The two are both made of quarried stone, meaning that they’ll both retain their integrity and hold up as time passes. Because of its less expensive shipping and installation costs, thin stone veneer is the ideal choice for adding natural stone into non-structural projects. Some types of thin stone veneer are also available in corner-shaped masonry units, meaning that a project can be extended around corners while maintaining the illusion of full building stone.

4. Not All Thin Stone Veneer Is Created Equal

Thin stone veneer products can be made from natural stone, but they can also be made from manufactured stone. Artificial or man-made stone is made from materials like Portland cement and aggregates. Oxide colors and other chemicals are used to give these man-made materials the look of natural stone. 

But while manufactured stone may look like natural stone during the installation process, the two won’t weather the same, particularly when used in exterior projects that are exposed to the elements. The chemicals in man-made stone are prone to fading over time. In contrast, natural thin stone veneer consists entirely of quarried rock—meaning that this material will retain its color and integrity as it weathers.  

5. There’s a Right and a Wrong Mortar for Thin Stone Veneer

If you’re a homeowner, you may not be at all familiar with mortar—but there’s more than one type of mixture out there. Of the five official types of mortar, type N, S, and M are the most popular. However, you still need to make sure that you’re using the correct mortar for the type of product you’re working with. If you choose a mortar with a higher compressive strength than that of your building material, for example, your masonry units could crack over time. Kafka Granite recommends type N or S for use with our natural thin stone veneer.

6. Installing Natural Stone Veneer Calls for a Professional

While it is possible for homeowners to install thin stone veneer on their own, we do recommend hiring a professional stonemason to ensure that this specialty building product is properly applied. A knowledgeable professional will be familiar with the necessary conditions and pre-installation steps that need to be taken, as well as the artistry behind blending shape, color, and pattern for a stunning outcome.

With the proper surface preparations, natural thin stone veneer can be adhered to a wide variety of surfaces, including plywood, concrete, and metal—but the surface of exterior projects will first need to be waterproofed. Depending on the material of the surface that will be in contact with the thin stone veneer, your stonemason may also need to apply additional materials, such as a non-corrosive metal lath. 

You might think following a DIY video or installation instructions online is all there is to creating a beautiful project with thin stone veneer, but even professional masons will get different outcomes with the same materials. Some simply have a better eye for arranging units than others. Because no two sections of natural thin stone veneer are the same, masons will have to meticulously fit pieces together, sometimes even altering them with a rock hammer or saw. Additionally, these professionals need to balance shape and color, whether by following a visible pattern or creating a more freeform mosaic. All of this is to say that you’re not just paying a professional stone mason for the labor—expertise and eye for design are also important factors.

Natural Stone Veneer From Kafka Granite

If you’re searching for a way to incorporate natural stone into your project, thin stone veneer offers an affordable, lightweight alternative to full veneer building stone. At Kafka Granite, we’re proud to offer a wide range of colors and cuts, ensuring that you find the perfect style of natural stone for your project. Contact us today to learn more about this specialty stone product.

The Geology of Natural Stone

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Designers, architects, and stone masons get to see quite a variety of stone products, from specialty aggregates to natural stone veneer. Even more people get to see the end results of Kafka Granite’s products—in the form of building facades, bridge overpasses, golf cart pathways, and more. But have you ever wondered about where that stone comes from, and how it came to be? Where, exactly, do we get these striking colors and high-quality material? 

Today, we’re backing up a few steps to take a look at the geology of natural stone. And don’t worry if you don’t remember anything from your middle school geology class—we’ve got you covered with this peek into the rock-solid foundation of our industry.

Where Does Natural Stone Come From?

Geology is an earth science that deals with understanding the structure of the planet. It also holds the key to every natural stone product out there. Before the Earth was a solid mass dotted with features like oceans and volcanoes, it was a ball of mineral gases. Natural stone is the result of those mineral gases solidifying and being compressed over millions of years. 

As the Earth’s crust solidified, heavier minerals were pushed towards the core of the planet, where they were subjected to intense pressure and high temperatures. Eventually, these newly solidified minerals were pushed upwards towards the surface, where they formed rock beds. Some of these deposits became the very quarries from which we extract our own natural stone today. 

3 Rock Types to Know

Quartz, granite, limestone, and marble are just some of the natural stones that we use in our products, but these various kinds of rocks can all be classified into three main types.

Igneous

To put it simply, igneous rocks were here first. This type of rock is created when liquid magma or lava cools down and becomes solid. If that process takes place below the surface of the Earth, it results in intrusive igneous rocks, like granite. But if the lava erupts and cools on the surface, we’re left with extrusive igneous rocks, such as basalt. You’ll find these kinds of rocks everywhere from basins to deep in the oceanic crust.

Sedimentary

Sedimentary rocks are fairly self-explanatory: they’re formed by solidifying sediments, such as volcanic ash. The distinctive mesas that litter the landscape of the American Southwest are a prolific example of sedimentary rock. The exact nature of the sediment determines the type of rock that is formed. Clastic sedimentary rocks, such as shale and sandstone, are created from pieces of pre-existing rocks that become compacted. Organic sedimentary rocks form from plant and animal debris being compacted over millions of years, while chemical sedimentary rock is created by dissolved minerals depositing and solidifying from water.

Metamorphic

Again, the name offers a hint: metamorphic rocks were once igneous or sedimentary rocks that underwent a transformation. That transformation involved extreme conditions, like high heat and pressure, that changed the chemical composition of the rocks. Metamorphic rocks include marble and quartzite, two popular choices for specialty aggregate and stone product manufacturers.

How Does Natural Stone Get Its Color?

If you’ve worked with natural stone before, you’ve likely noticed that no two pieces are exactly the same. In fact, this is one of the major draws of natural stone as a building material; the color variations add a kind of character that is difficult to replicate with man-made products. 

So, where does natural stone get its array of colors from? It’s all thanks to the nature of the minerals and other organic components that make up each type of stone. Depending on the exact minerals and the way in which they settle, blocks of stone extracted from the same quarry can vary greatly in color, texture, and pattern. Marble, for example, is widely known for its veined pattern. Those veins are caused by deposits like iron oxide and feldspar. The “purest” marble is largely white and free of color variation, but particular varieties are actually sought after to lend a certain look or color to a project.

Applications of Natural Stone

It’s worth noting that different types of rocks are useful for different building purposes, depending on their hardness and other key physical properties. There are ASTM Standards set out that describe the minimum and maximum specifications for a variety of natural stone types, which is invaluable for quality control. 

Today, natural stone is extracted from quarries around the world—Kafka Granite owns a number of them across North America. While our business isn’t nearly as old as the rocks that we crush into specialty aggregates, our decades in the industry have shown us that there are nearly endless uses for natural stone. The material is ideal for thin stone veneer products, where all the color variations of a stone can be put on display. Natural stone can also be used in the creation of retaining walls, accent pieces, pathway mixes, and a whole host of other applications. 

Incorporate the Beauty of Natural Stone Into Your Project

Whether you’re an architect seeking a solution for a large commercial project or a designer planning out a rustic, farmhouse-style home, Kafka Granite has the right product for your unique needs. We’re eager to help you find the ideal natural stone product for your project. Contact us today to speak to a knowledgeable sales representative.

The Unique Geology of Wisconsin

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Though Kafka Granite sources stone from quarries across the continent, we’re proud to call Wisconsin our home—and the wellspring of many of our beautiful products. But what, exactly, makes this great state the perfect spot for our business? 

Essentially, it’s all in the geology of the area. We’ve put together an overview of the thousands of years of history and natural forces that have made Wisconsin’s geology so unique today. Read on to learn more about this fascinating state.

Wisconsin Stone Over the Centuries

Wisconsin’s uncommon geology didn’t happen in a year—or even a century. It took hundreds of thousands of years for Earth’s cooling and heating patterns to transform the area into what it is today. More specifically, we have glaciers to thank for the vast majority of Wisconsin’s mineral deposits and topography.

The Wisconsin Glaciation

About every 100,000 years, the planet goes through a long period of cooling, followed by a shorter period of warmth. The last occurrence of this cycle, known as the Wisconsin Glaciation, began about that long ago—with the Laurentide Ice Sheet advancing across North America. Large swaths of Wisconsin became covered in ice, which was diverted and interrupted by the natural topography of the area. 

It took thousands of years for the ice to halt its approach and for the glaciers and sheets to melt or retreat from Wisconsin, but that slow process left us with a natural landscape unlike anything else seen in U.S. geology. The shrinking Laurentide Ice Sheet left behind the many lakes and rivers that characterize parts of the state, as well as a wide variety of glacially deposited minerals—the very minerals that create many of the colors in Kafka Granite’s collection!

A Wealth of Minerals

Wisconsin contains deep deposits of iron and other ores, which have characterized the state—just look at the University of Wisconsin’s mascot, Bucky Badger, an homage to the local lead miners of the early to mid-1800s. But you can also find deposits of minerals and gemstones from A to Z across the length of the state. Quartz and calcite are just two extremely common finds.

Decomposed Granite in Wisconsin

Wisconsin’s unique geologic makeup, coupled with thousands of years of natural erosion, also resulted in large deposits of decomposed granite (DG) throughout the state. When feldspar, one of the main components of granite, breaks down, it results in flaking, crumbling material that can be further crushed for projects like pathways and baseball fields. Wisconsin boasts a variety of hues of naturally occurring decomposed granite, from bold reds to vibrant golds.

Decomposed granite mining is limited to certain geographical locations throughout the country, but Wisconsin is particularly rich in this material. Today, DG is extracted from the ground, then sent through a screening process. If needed, this natural resource can be crushed to specific sizes and gradations to meet specifications for a particular mix or project. 

What Does Wisconsin’s Geology Mean to Kafka Granite?

Thanks to the rich landscape created by the last Ice Age, Wisconsin offers an invaluable variety of materials, from natural round boulders to crushed quartz, granite, and marble in a startling range of colors. This selection enabled the rapid growth of Kafka Granite—because we were able to source and acquire so many different colors quickly, and in close proximity to our home base.

A Variety of Colors and Stone Products

This level of variety is not normal in much of the country. Head to another state, and you’ll see nothing but gray limestone for miles. Some areas of the country may not have any granite at all, or may only have one such deposit. It’s not easy to source all of these colors if you’re in the middle of Kentucky, for example. 

Wisconsin’s geology—and that of its surrounding states—allows Kafka Granite to source materials like black, pink, and gray granite, or gray limestone, all within 200 miles. In Pennsylvania, you’ll find more gray granite than you can use, but you won’t find the same range of other products and colors. 

It’s that level of convenience that has allowed us to meet the needs of architects, designers, and stonemasons around the country. In fact, about 85 percent of our colors are sourced from Wisconsin or the Upper Peninsula. 

We have an immense variety of naturally occurring materials, which you can even pick up on from the comfort of your car. The next time you’re in the area, take a drive around the state—notice the shoulders of the road, which are created from whatever stone is locally abundant. You’ll see shades like purple, gray, and green, all of which will tell you that there’s an abundance of stone that color in the area. Around our facility, you’ll notice plenty of gray and black granite.

Natural Stone Products From Kafka Granite

We’re immensely proud of the hard work and entrepreneurial spirit that has made Kafka Granite a leading manufacturer and supplier of specialty aggregates and other building products. Clearly, beautiful, rugged Wisconsin has played a pivotal role in the growth of our company over the years. Not only is it home to our crushing facility; but Wisconsin’s geology means that it offers plenty of natural resources and mineral deposits to satisfy the high demand for unique colors and products.

If you’re looking for natural stone products in a wide variety of colors and sizes, you’ve come to the right place. Contact Kafka Granite today to speak to a knowledgeable sales rep about your project.

Galaxy Castle

An Overview of Kafka Granite Natural Stone Veneer Products

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Architects, designers, masons, and homeowners have long valued the look of natural stone—but one thing that stops a lot of projects before they even get started is the price of materials. High-quality natural stone can be expensive due to shipping and installation costs. As a result, some designers have had to make do with artificial stone or brick. Kafka Granite has a better solution: a range of products that can incorporate the beauty of natural and stand the test of time. Here’s a look at our natural stone veneer product offerings and some insight into how we came to produce specialty building stone.

When Did Kafka Granite Begin Producing Natural Stone Veneer Products?

As one of the largest suppliers of specialty aggregates and crushed stone in the country, we’re always looking for new ways to utilize these natural resources. Our decades of experience in the stone industry perfectly positioned Kafka Granite to expand into specialty building stone. Last year, we debuted our own line of natural stone veneer products.

Our newest, 700-acre quarry provided a launching point for a range of unique natural building stone products. This quarry offered mica-enriched quartzite that sparkled with shades from green to black, and Kafka Granite Founder Glenn Kafka knew that he had found something special. While this quarry may have been the inspiration for our thin stone veneer products, it was only the beginning. Our product line has since expanded to include thin stone veneer in a variety of classic Kafka colors and cuts. 

Natural Stone Veneer Products From Kafka Granite

We source our stone from quarries all over North America and ensure that our materials meet the highest quality standards. We’re pleased to offer the classic colors designers, contractors, and builders have come to know and love, as well as several unprecedented, glittering options to add that extra “wow” factor to any project. 

Our selection of natural stone veneer products includes granite, quartz, and marble building stone. Here’s an overview of what you can expect in terms of color and cut. For a more comprehensive look into the various cuts we have available, take a look at our breakdown of the different types of thin stone veneer cuts.

Colors

  • Chateau Granite: unique blend with grays, blacks, and hints of pink
  • Galaxy Glitter: sparkling blend of deep gray to black tones
  • Gun Metal Marble: cool-toned, blue-gray marble 
  • Imperial Gray Granite: deep gray granite
  • Misty Gray Marble: light gray marble
  • Sedona Glitter: shimmering blend with warm burgundy, desert, and rose tones
  • Sierra Granite: taupe-gray granite
  • Starlight Granite: a rich black granite

Cuts

  • Ashlar Cut: natural split face showing off the interior of the stone
  • Castle Cut: sophisticated square cut
  • Dimensional Cut: consistent heights for clean lines
  • Mosaic Cut: irregular, rugged look
  • Rustic Cut: natural seam face showing off the exterior of the stone
  • Heritage Blend: old-world country charm
  • Sawn Dimensional: smooth, sawn face and consistent heights

The Specs

Kafka Granite’s natural thin stone veneer has a nominal thickness of ¾” to 1½”, and each square foot weighs between 10 and 15 pounds. Our products meet the ASTM specifications for thin stone veneer, which require specific measurements for compressive strength, modulus of rupture, flexural strength, and absorption, and bulk specific gravity. As with any Kafka Granite product, we run rigorous quality assurance tests on our specialty building stone material to ensure that every masonry unit meets our high standards. 

The Future of Kafka’s Natural Stone Veneer Product Offerings 

With our extensive network of quarries and commitment to excellence and innovation, we’re constantly working to develop exciting new products and different variations of our current offerings. With only 60 of over 700 acres exposed in our newest quarry alone, the future looks bright—and colorful. Be on the lookout for more striking hues to be added to our selection of natural stone veneer products.

Incorporating Natural Stone Veneer Into a Project

Natural thin stone veneer is a wonderful material choice for a number of reasons. Its light weight, versatility, and affordability make it ideal for non-structural projects large and small. Because thin stone veneer doesn’t require special footings for installation, it can bring the stunning look of natural stone to installations from building facades to interior features. Our stone veneer products have been used by both architects and homeowners to make projects stand out. To maintain the integrity of the product, we recommend letting a professional stonemason hire the installation.

Complete Your Project With Kafka’s Natural Stone Veneer

Whether you’re a designer sourcing material for an expansive exterior installation or a homeowner looking for the right natural stone for a fireplace facade, Kafka Granite has you covered with a variety of natural thin stone veneer options. Contact us today to discuss your project—we’re happy to connect you with a knowledgeable representative who can speak to your unique needs and provide a quote or free sample. We look forward to helping you incorporate the beauty of natural stone into your project.

Kafka Granite manufacturing

The Importance of Quality Control in Stone Products

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The importance of quality control throughout the natural stone quarrying, crushing, and fabricating process can’t be overstated. In fact, all quality stone products require a certain level of testing and oversight during their manufacturing process. Why? Because in order to create reliable, manufactured aggregates and other stone products like thin stone veneer, you need to start—and finish—with high-quality, consistent material. 

Whether you’re sourcing quality architectural aggregate or commercial landscaping materials, you need to be sure that you’re getting the best material for the job. That quality assurance you’re looking for starts as soon as natural stone is extracted from a quarry and extends throughout the manufacturing process. 

Kafka Granite supplies products that are used for a wide range of applications, such as architectural precast concrete, terrazzo flooring, manufactured quartz countertops, epoxy resin tile, and more. But we didn’t become one of the largest manufacturers and suppliers of specialty aggregates and other stone products in the country through sheer luck—our work requires high-quality materials and careful adherence to set standards. Here’s why it’s so important to monitor and control the quality of stone products.

Why Is Quality Control Critical in Granite and Other Natural Stone Processing?

Not all quarried stone is the same. The quality of the natural stone you source for a project will play a significant role in the overall look of the finished installation—and its continued performance. Your completed building facade might look stunning as the mortar dries, but how will it look five years later? What about five decades? Natural thin stone veneer, for example, should weather beautifully and retain its structural integrity over time. But imposter products, or artificial stone passed off as natural stone, will not yield the same results. 

Price is a factor in any project, and you may be tempted to go with the cheapest option around. But that road may lead to ruin in the form of imperfect stone products that don’t stand the test of time. For instance, precast concrete manufacturers need consistently sized aggregates to use in their mix designs, or their machines will produce varying results—rather than uniform product. Consistency is also critical in pathway materials. These mixes need to meet a certain gradation specification in order to work properly with their binders, and a poorly graded aggregate or incorrectly mixed binder will affect the outcome of the project. Before you get taken in by the price tag, be sure to ask your supplier for the specifications of their products, so that you can ensure you’re getting reliable materials.

What Goes Into Creating Quality Stone Products?

At Kafka Granite, we pride ourselves on producing architectural and landscape aggregates, along with specialty building stone products, that meet industry standards and perform admirably in a wide range of projects. Let’s take a quick look at what goes into the manufacture and installation of quality stone products.

Industry Standard Tests

To remain compliant and produce reliable products, manufacturers need to adhere to quality assurance specifications, regulatory standards, industry standards, and any other regulations that pertain to their natural stone products. A number of these standards are set down by ASTM International, a non-profit organization that develops technical standards for materials and products across a wide range of industries. 

Kafka Granite runs industry standard tests on all of our stone products, evaluating our crushed stone for criteria such as absorption, Moh’s hardness, and specific gravity, as well as regular sieve analysis. All of our thin stone veneer is tested for ASTM C615, the Standard Specification for Granite Dimension Stone. This test data is made readily available to our customers.

Installation Education

We don’t keep our knowledge to ourselves. Education is crucial to the proper installation of many of our products, both to ensure efficient use of the installing contractors’ time and to create a beautiful final result. When working with contractors on installations, we make sure they have the knowledge needed to get the job done correctly. That includes an understanding of the proper conditions under which to install a certain product and the proper tools needed for the job. Our Stabilized Pathway Mix, for instance, should have an 8-10% moisture content for ideal installation. We recommend the snowball test or step test to make sure that the mixture has been prepared properly. We also provide information on the amount of subgrade you’ll need, as well as base construction, surface watershed management, spreading, and compaction.

Innovation

As a leader in the specialty aggregate industry, we are constantly making strides in new applications and manufacturing processes that can improve products while maintaining quality. We work closely with our industrial and manufacturing customers to source aggregates that perform best with their processes, ensuring that they receive the materials they need to produce excellent finished products. And when it comes to pathway materials, Kafka Granite is proud to source some of the best binders in the industry. We recently sourced a polymeric wax that is proprietary to Kafka Granite. Our Wax Polymer Pathway Mix is currently patent pending. This particular pathway mix has proved extremely useful on golf course pathways and other pathways that need to withstand both heavy erosion, but maintain a natural look and feel..

Exceed Standards With Kafka Granite

Here at Kafka Granite, we put time, effort, and a lot of research into creating high-quality crushed aggregates and specialty building stone products. We’re proud to adhere to all industry standards and act as an example of manufacturing excellence in the specialty aggregate and crushed stone industry, and look forward to providing classic and innovative stone products for years to come. Give us a call today—we’re always happy to answer questions about our products, help you with a unique project, or provide samples.