A metamorphic rock formed by the alteration of sandstone due to heat, pressure and chemical activity. The layers found within quartzite materials are very hard. Due to the incredibly high abrasion resistance of quartzite it can be difficult to quarry and fabricate. This affects availability, fabrication lead times and cost. Some quartzites have high absorption ratings and will stain when exposed to oil and highly-pigmented liquids. Most quartzite has naturally occurring cracks and fissures.