is a metamorphic rock formed when quartz sands are subjected to extreme heat and
pressure due to tectonic forces. Pure quartzite is white. The individual quartz
crystals are generally visible.
Like a marble, color and patterns in quartzite
are the result of impurities. Quartzite is very hard (unlike a marble), having a
Mohs hardness of 7 (it easily cuts glass), and is
not acid or water soluble. Being thus resistant to weathering, it often forms ridges and