Each day I am learning more and more about quartzites. I have to admit that up until about 2 years ago, I was not very familiar with quartzite at all. Quartzite is a metamorphosed sandstone comprised of mostly fine grained quartz. Our company is directly importing slabs of this exotic and beautiful material from Brazil. I have talked to some of our suppliers about the stone, and I was surprised to find that their knowledge of quartzites is very limited. In fact, many quartzite colors are sold as “granite” to U.S. companies. This is a shame because quartzites have their own unique properties that should be appreciated.
First of all, the grain size is much finer than granite. This gives the stone a softer, almost marble-like appearance. Typically the slabs have a smooth flowing grain direction that resembles a painting with blended colors verses the hard, instantaneous color changes common to granite. So far, I have seen a wide color range of quartzites including green, grey, and red varieties.
When cutting quartzite, one will soon learn of its extreme hardness. This can come as a surprise because of its powdery grain and marble look. Don’t be fooled, use plenty of water, and keep your diamond blade dressed!
Another piece of advice for fabricators – Don’t hammer off a sample from a slab. The stone doesn’t break off exactly where you expected, and a larger area around the sample will fracture in a spider web pattern. For practical purposes as a kitchen countertop, I think quartzite is an outstanding material. I have tested several different types of quartzite for staining, scratching, and etching. Of all the stones that I tested, none were etched by acidic products commonly found in the kitchen. I tested lemon juice, vinegar, and ketchup with the same result. Imagine that - The elegant look of marble without the fear of etching!
When properly sealed, I found that I couldn’t get anything to stain it either. Again, I tested several different colors with common stain producing products.
I tested for scratching as well. I found that quartzite can be scratched, but not easily. You have to use something very hard like the rough corner of a piece of granite. Even then, the scratch is very fine and not easily seen. I found quartzites are harder to scratch than many granites.
Of course, not all quartzites are exactly the same. Each color has its own unique characteristics. For instance, Luce de Luna ( white with soft gray / greenish veins) would not stain, but is instantly darkened by any moisture even when sealed thoroughly. The darkened areas will dry out within minutes, but this could definitely be a nuisance to a homeowner.
I suppose the best advice I could give someone considering a quartzite or any other natural stone as a countertop would be to take a large sample home and perform your own tests on the stone. There is a vast amount of information available on the internet and throughout the stone industry – helpful, confusing, conflicting, or just plain wrong.
Get familiar with your stone before making your final decision.