Quartzite is a very confusing natural stone for most people. Researching the stone on the internet doesn’t help much either. One site will say it etches and another will say it doesn’t. There is a lot of inconsistent information on quartzite identification and what characteristics it possesses. So why is the information mixed? That’s most likely because quartzite is commonly mislabeled. There is the real quartzite, then there is marble or dolomitic marble that are often mislabeled as quartzite. Real quartzites’ properties are very consistent. Let’s get to know the real quartzite.
Quartzite is a metamorphic stone that is almost completely composed of mineral quartz. Similar to the process of billions of snowflakes merging together to form a solid iceberg, quartzite is composed of sand grains that form sandstone that is buried very deeply in earth which becomes hotter and more compressed over time. The grains of sand fuse to each other under the heat and pressure and form a very dense and durable stone.
Quartzite is typically light colored or even white due to the light color of quartz sand. Minerals in the groundwater can impact the color with blue, green, or red hues. Some types of the more vividly colored quartzite are Azul Macaubas and Van Gogh quartzites.
Quartzite is a very hard stone. This is one of the key ways to separate quartzite identification from its imposters. On the Mohs Hardness Scale of 1-10 with one being talc and ten being diamond, quartzite rates as a seven. This means that it’s harder than the blade of a knife and harder than glass. If you see “soft quartzite” on the label then it’s not real quartzite, there’s no such thing as soft quartzite.
Quartzite is resistant to acids and will not etch from acids such as vinegar or lemon juice. If it etches it’s not real quartzite. Quartzite does have a wide range of porosities. The highly metamorphosed stones have minerals that are tightly bonded together, such as Sea Pearl or Taj Mahal. Some quartzites have been exposed to less intense pressure, such as Calacatta Macaubas, and White Macaubas, which makes them more porous making sealing them a good idea.
So how do you determine if it’s real or fake quartzite? Doing a glass scratch test is one way to verify that quartzite identification is real. To complete the test you will need to:
Have a glass tile that can be damaged
Have a piece of the stone, a pointy edge is ideal
Press hard with the stone to try to scratch the glass
Inspect the scratch closely. Is the scratch really a scratch, or is it actually a powdered trail of the stone that crumbled?
Repeat the test with different areas of the stone if it is variable and has more than one color or type of mineral in it
A similar test can be done with a knife blade. This test is ideal if no pointed edges are available, such as with a full finished slab. Use the tip of the knife blade to try to scratch the stone. If it’s real quartzite it will only scratch lightly or not at all.
An etch test can also be completed. Placing vinegar or lemon juice on the surface of the slab for about 15 minutes will reveal if the stone is real quartzite. If the stone is unaffected after wiping off the acidic liquid, then it’s the real deal. If the area is etched and appears as a dull, lighter, or darker area then it’s not real quartzite. Keep in mind that extremely acidic liquids such as rust stain removers can etch extremely strong stones like quartzite or granite.
Some things that can’t be relied on to distinguish real quartzite from non-quartzite are the price, name of the stone, or country of origin. It’s highly likely that you will not be able to tell the difference between even quartzite and marble. That is why the tests are so helpful.
Now that you know some of the ways to identify real quartzite, you can appreciate the individual beauty of the natural stone. If you want to check out natural stone materials for yourself, stop by G.M.S. Werks and check out our showroom for your natural stone needs! Our hours of operation are Monday through Thursday from 8:00 am to 5:00 pm and Friday from 8:00 am to 4:00 pm. You can also reach us by phone during our normal business hours at 402-451-3400 or email us by going to the contact page of our site!