What Is Quartzite?

What is quartzite anyway, and why would I be interested in using it in my home? Well, here is some information that will give you an idea of the consistency of quartzite and how it’s best used.

What Is Quartzite?

Quartzite is a metamorphic rock that is made almost specifically from the mineral quartz. Metamorphic means that the rock itself underwent a transformation through heat and pressure or other natural means. The life of the rock began from either the bed of a river, a beach, or a dune. With the passage of time, the actual sand grains came together and were compressed and formed into sandstone. Once the sandstone is buried underneath layers of rock, it gains heat and is compressed. With sufficient heat and pressure, the sand grains change shape and are merged to form a strong rock.

Because quartzite is white or lighter in color, there are other minerals that can get into it through groundwater that give it variations in color such as blue, green or red, but despite its color, quartzite is made from quartz. It’s easy to identify it from other minerals.

Quartzite Hardness

Quartzite is known for its hardness and durability, and the way to determine whether you are actually getting the real deal is to test its hardness. Since it measures 7 on the Mohs hardness scale, you’re dealing with a substance that is harder than glass and the blade of a knife. You can do this yourself by testing with a sample of the stone.

Testing for Quartzite

If quartzite is not labeled correctly, then how do you know what kind of rock it is? There are different tests you can do to determine its credibility. One is the glass test which involves:

  • Using a glass tile sample
  • Finding a rough part on the rock sample
  • Putting the glass tile on a table
  • Scratching and pressing the rock sample
  • Inspecting the scratch
  • Deciding whether it’s a scratch or is it powdered trail of crumbled rock
  • If the sample has more than one color or mineral in it, repeat the test


If quartzite is real, it will easily scratch the glass. There will be a grinding and you’ll feel it go into the glass. The scratch will be apparent and you’ll definitely have quartzite. If it’s not quartzite, there will be a slight scratch and the piece will have a slippery feel while it’s on the glass. There is no noise and a powdery area is left that will rub off.

Other Tests

A test similar to the glass is done with a knife blade. You want to scratch the top of the rock with a blade tip. If the stone is genuine quartzite, it will lightly scratch or won’t scratch at all. If you are questioning whether the piece is marble or dolomitic marble, it will scratch easily.


You can try to use lemon juice or vinegar on the slab’s surface and allow it to remain there for at least 15 minutes. When the time has elapsed, wipe the area clean and see if it has affected the stone. If it etches, it will look like a lighter or darker area or an area that has become dull. With exposure to acids, such as lemon or vinegar, marble will exhibit etching, while dolomitic marble will display subtle etching. Quartzite will show no etching. You want to be careful that you don’t use a strong acid that’s found in rust stain removers that can show etching even on granite and quartzite.

These three different tests will serve to let you know whether you have a true sample of quartzite and will allow you to solve the quartzite mystery, plus give you the experience of discovering firsthand whether you have a genuine piece of quartzite.

Distinguishing Quartzite

There are distinguishing characteristics of a stone that make it what it is. The country of the stone’s origin, its price or the name of the stone are not the best indicators whether you have quartzite in your hands. In so many cases, it’s impossible to tell whether you have marble or quartzite and if you’ll be able to tell them apart visually. That’s why the different testing methods are accurate. Though they look a lot alike, they are very different and that’s why testing is important to determine their differences.

Differences Between Quartzite, Granite and Marble

Often quartzite is mislabeled as granite. When you look at granite, it has flecks of darker colors in it while quartzite is usually lighter or has flowing areas of color. That’s not such a big deal as both stones have similarities. Both are harder than glass, and neither one will show the effects of etching by acids. They are, however, in different classes. That’s not important as how they both will act on a countertop or as a floor tile.

Super White is dolomitic marble which simply means that it doesn’t scratch glass but it will etch. Sometimes it is caught in the quartzite and marble confusion. Super White will have a few hints of quartz mixed in with the marble, but it’s still marble and will act like marble. Try the glass test with Super White and test different areas of the stone to get an idea of how it’s different. You’ll find that other parts are both hard and soft. It’s confusing, but it’s apparent that the stones look alike and the information out there brings conflicts with what kind of stone you actually have.

Fantasy Brown is another stone that brings confusion in the struggle to find true quartzite. Since Fantasy Brown is layered, some layers are marble while others are quartzite. You want to treat it as though it’s marble. Again, try the glass or acid test on the layers and you’ll be able to discover the differences.

With all this information out there and what’s given here, you should have a pretty good understanding of what quartzite is and how to differentiate it from other stones. If for some reason you’re still not sure of what quartzite is and how it will fit in your home, fill out the contact form and a representative will get back to you with the answers you need to satisfy your curiosity.