metamorphic
Quartzite
Quartzite (chiefly SiO2)
AI-generated identification · may be incorrectHardness (7 on Mohs scale), color typically white to gray but can be brownish due to iron staining, vitreous (glassy) to dull luster, granular texture, lacks cleavage, specific gravity is roughly 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 (7 on Mohs scale), color typically white to gray but can be brownish due to iron staining, vitreous (glassy) to dull luster, granular texture, lacks cleavage, specific gravity is roughly 2.65.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. Under high heat and pressure, quartz grains recrystallize and fuse into a solid, interlocking network. Most formations range from Precambrian to Paleozoic ages.
Uses & applications
Used as crushed stone for road construction, railway ballast, and as a decorative stone in landscaping. High-purity quartzite is used to produce glass and metallurgical silicon.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during erosion, forming ridges and mountains. It is significantly harder and more durable than the sandstone from which it originated.
Field identification & locations
Identify in the field by its hardness (it will scratch glass) and its crystalline, sugary appearance. Unlike sandstone, quartzite breaks across the individual quartz grains rather than around them. Found globally in mountainous or metamorphic terrains.
More like this
Other metamorphic specimens
Nephrite Jade
Nephrite
Mineral/Rock
Amphibolite
Amphibolite
metamorphic
Rhodonite
Manganese Silicate (Mn, Fe, Mg, Ca)SiO3
mineral
Rhodonite
(Mn,Fe,Mg,Ca)SiO3
mineral
Greenschist
Greenschist (containing Chlorite, Actinolite, and Epidote)
metamorphic
Garnet
Garnet group: X3Y2(SiO4)3 (commonly Almandine-Pyrope series)
mineral