metamorphic
Quartzite
Quartzite (Metamorphosed quartz sandstone)
Hardness of 7 on the Mohs scale, colors range from white and gray to pink, yellow, or greenish due to impurities, vitreous to greasy luster, non-foliated crystal structure, conchoidal fracture, specific gravity of 2.65 to 2.70.
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, colors range from white and gray to pink, yellow, or greenish due to impurities, vitreous to greasy luster, non-foliated crystal structure, conchoidal fracture, specific gravity of 2.65 to 2.70.
Formation & geological history
Formed under high heat and pressure when quartz-rich sandstone is subjected to regional or contact metamorphism, typically during mountain-building events over millions of years.
Uses & applications
Used in construction, as crushed stone for roadbeds, railway ballast, manufacturing of silica brick, and sometimes as a decorative dimension stone or in countertops.
Geological facts
Quartzite is extremely durable and resistant to chemical weathering, which is why quartz-rich ridges often survive as prominent hills or mountains while surrounding softer rocks erode.
Field identification & locations
Can be identified in the field by its hardness (it will scratch glass easily and cannot be scratched by a knife) and the fact that it breaks across the quartz grains rather than around them.
More like this
