Quartzite is one of nature’s most precious natural stones and has become increasingly popular due to its extremely durable surface, unique patterning, and diverse colors. Whether you are using quartzite for your countertops in a high-traffic kitchen or a statement wall application, here are all of your questions answered about this incredible and highly sought after stone.
How is quartzite formed?
Quartzite evolves from sand grains, which is why it is found in areas with beaches, desert dunes, or riverbeds. As sand grains are buried and compressed, they fuse together to form sandstone. As the sandstone continues to be buried deeper and deeper, more heat and pressure cause the sandstone to compress. In this state, the sand grains lose their original shape and transform into quartzite.
Because quartzite evolves from sand grains, it is no surprise that much of quartzite, such as Taj Mahal, is lighter in color. On the other hand, in parts of the world such as Brazil, minerals are carried through the sand grains by groundwater, creating some of the most unique and colorful quartzite. Fusion Wow, Emerald Green, and Red Louis are all great examples of this geologic phenomenon.
Will quartzite scratch or etch?
This long and tedious process of sand compression and heating leads to an incredibly dense and durable stone. To put this in perspective, the Moh’s Scale of Mineral Hardness classifies quartzite at a 7, higher than its neighbor granite, which on the same scale measures between 6-6.5. To further illustrate, a kitchen knife and glass are measured at a 5 on the Moh’s hardness scale. Therefore, scratches should not be an issue when using quartzite in your home, even in high traffic areas and highly used spaces, such as the kitchen.
If you cook frequently and want to make sure that your countertops are safe from etching, then you might want to also consider quartzite. Quartzite will not etch from acids found in household items such as vinegar and lemon juice. However, both quartzite and granite will react to hydrofluoric acid, which is found in some rust removers. Thankfully, hydrofluoric acid is not a common ingredient in household products.
Will quartzite stain?
All quartzite is different in terms of porosity and stain resistance as it depends on how tightly the minerals bonded together during the mineral metamorphic process. In general, quartzite such as Sea Pearl and Taj Mahal have highly bonded minerals, while Macaubas may have been exposed to less pressure, making it more porous and prone to staining. Staining from household items can be avoided by using a sealer, which is typically provided by the installer. To maintain this coverage, it is recommended to seal your quartzite about once a year with a home application sealer.
What is soft quartzite, calcitic quartzite, or dolomitic quartzite?
According to the Marble Institute of America, there are many products on the market that are labeled as “soft quartzite,” “calcitic quartzite,” and “dolomitic quartzite”. Note that these products share only some of the same properties as quartzite. With marble, calcite, and dolomite all rated around a 3 on the Moh’s hardness scale and quartzite rated at 7, these varying labels are typically trying to convey that they fall somewhere between a 3 and a 7 on the Moh’s hardness scale. Meaning, they are harder than a marble, calcite, or dolomite, but softer than a quartzite.
It is important to be aware of the difference as marble, calcite, and dolomite are softer and therefore more susceptible to scratching, etching, and staining than a true quartzite. Of course, these effects can be lessened by using a sealer, but it is helpful to know beforehand to avoid any misunderstandings.
How do I test to see if I have a true quartzite?
As mentioned above, household kitchen acids such as lemon juice and vinegar will not etch quartzite. One way to test if you have a true quartzite is to put lemon juice or vinegar on your stone and let it sit. Wait for 15 minutes and then wipe up your test area and look for an etch. Depending on the coloring of the stone, etching may look more dark, light, or dull than before. If any etching occurs then it is not a true quartzite. For this test, sometimes it helps to take before and after pictures to best compare the results.