Quartzite is a metamorphic rock formed when quartz-rich sandstone or chert has been exposed to high temperatures and pressures usually related to tectonic compression within orogenic belts. \u00a0Such conditions fuse the quartz grains together forming a dense, hard, equigranular rock. The name quartzite implies not only a high degree of induration (hardness), but also high quartz content. Quartzite generally comprises greater than 90% percent quartz, and some examples, containing up to 99% quartz, and are the largest and purest concentrations of silica in the Earth’s crust.<\/p>\n
Although quartz-rich sandstone can look similar to quartzite, a fresh broken surface of quartzite will show breakage across quartz grains, whereas the sandstone will break around quartz grains. Quartzite also tends to have a sugary appearance and glassy luster. \u00a0The variety of colors displayed by quartzite is a consequence of minor amounts of impurities being incorporated with the quartz during metamorphism. Although quartzite can sometimes appear superficially similar to marble, quartzite will not be scratched by a metal blade, and will not fizz on contact with dilute hydrochloric acid.<\/p>\n
Quartzite is granular, medium grained and hard.\u00a0 Generally it feels gritty to touch.\u00a0 Pure quartzite is white but quartzite exists in a wide variety of colors.<\/p>\n
As a building stone, Quartzite is used as a dimension stone for building facings and paving.<\/p>\n
Quartzite was used on the Graham County Courthouse in Robbinsville, NC.<\/p>\n
Photos:<\/strong><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Quartzite is a metamorphic rock formed when quartz-rich sandstone or chert has been exposed to high temperatures and pressures usually related to tectonic compression within orogenic belts. \u00a0Such conditions fuse the quartz grains together forming a dense, hard, equigranular rock. The name quartzite implies not only a high degree of induration (hardness), but also high … <\/p>\n