Great article from USENATURALSTONE.COM by Karin Kirk. Click here for the full article http://usenaturalstone.com/definitive-guide-quartzite/
You'll find pretty much all you need to know about Quartzite in this article.
One important clarification you should note is that Quartzite IS NOT the same as "Quartz" countertops also known as "engineered stone", which are man made. More on that subject coming in another blog post.
The article is a great read. If your pressed for time though, my notes here may come in handy:
The confusion about Quartzite
Quartzite may be the most confusing natural stone out there. There is an unsettling disparity of information available. Further quartzite is commonly mislabeled. Some quartzite is the real deal, but sometimes marble or dolomitic marble are labeled as quartzite.
What is Quartzite?
GEOLOGICALLY SPEAKING: Quartzite is a metamorphic rock made almost entirely of the mineral quartz. Quartzite begins its geologic life as sand grains. Over time, the sand grains become compressed to form sandstone. As the sandstone gets buried ever more deeply underneath layers of rocks, it gets hotter and more compressed. The sand grains lose their original shape and fuse together forming a dense, durable rock: Quartzite.
Properties of Quartzite
Quartz (Quartzite) is hard. 7 out of 8 on the Moh’s hardness scale. Harder than Granite.
Quartzite WILL NOT ETCH from lemon juice or vinegar.
Quartzite has a RANGE OF POROSITY. To be safe best to seal them with a quality sealer.
Quartzite and marble can look very similar. Quartzite (and most granites) will scratch lightly or not at all with the edge of knife. Marble will scratch easily.
Geology is your friend
Thankfully, the properties of Quartzite make it somewhat easy to identify. Being informed about your stone is the way to go.
You can view our current selection of Quartzite here: www.arcstonegranite.com/quartzite