metamorphic
Quartzite
Quartzite (composed primarily of SiO2)
Hardness: 7 on Mohs scale; Color: typically white to gray, can be yellowish or pink; Luster: vitreous to dull; Crystal Structure: Trigonal (granular texture); Fracture: conchoidal or irregular.
- Hardness
- 7 on Mohs scale
- Color
- typically white to gray, can be yellowish or pink
- Luster
- vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: typically white to gray, can be yellowish or pink; Luster: vitreous to dull; Crystal Structure: Trigonal (granular texture); Fracture: conchoidal or irregular.
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure during regional metamorphism, causing the quartz grains to recrystallize and fuse into a solid rock.
Uses & applications
Used as a decorative stone in construction, as crushed stone for road gravel and railroad ballast, in the manufacturing of glass and ceramics, and as a durable countertop material.
Geological facts
Quartzite is so hard and dense that it will break through the quartz grains rather than around them. It is one of the most chemically and physically resistant rocks found on Earth’s surface.
Field identification & locations
Field identification can be done by its extreme hardness (scratches glass easily) and granular 'sugary' appearance. It is commonly found in folded mountain belts and ancient cratons globally.
