metamorphic
Quartzite
Quartzite (Metamorphic Quartz Arenite)
Hardness of 7 on the Mohs scale, white to grey color with darker mineral speckles, vitreous to greasy luster, non-foliated massive crystal structure, concoidal fracture, specific gravity around 2.65.
Identified More metamorphic →
Explore Quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, white to grey color with darker mineral speckles, vitreous to greasy luster, non-foliated massive crystal structure, concoidal fracture, specific gravity around 2.65.
Formation & geological history
Formed from quartz-rich sandstone (quartz arenite) under high temperature and pressure conditions during regional or contact metamorphism, often over millions of years.
Uses & applications
Used in construction, as crushed stone for road bases, railway ballast, dimension stone, and occasionally in decorative landscaping.
Geological facts
Unlike sandstone which breaks around sand grains, quartzite breaks straight through the quartz grains because of the intense heat and pressure fusing them tightly together.
Field identification & locations
Identified by its high hardness (scratches glass easily), lack of effervescence with acid, and the fused sugary texture visible on broken surfaces. Common worldwide in mountainous regions and ancient cratons.
More like this
