Quartzite

Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts.

Both granite and quartzite are very hard, but on the Mohs scale of hardness (from 1 to 10, with 10 being hardest) quartzite has the slight edge. It measures around 7 whereas granite measures around 6 to 6.5. While quartzite is slightly harder than granite, it’s important to understand that it’s not bullet proof.m.