metamorphic
Quartzite
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale. Color: White, gray, or tan (iron staining can cause yellow/orange). Luster: Vitreous to dull. Crystal structure: Trigonal (granular). Cleavage: None. Specific Gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- White, gray, or tan (iron staining can cause yellow/orange)
- Luster
- Vitreous to dull
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: White, gray, or tan (iron staining can cause yellow/orange). Luster: Vitreous to dull. Crystal structure: Trigonal (granular). Cleavage: None. Specific Gravity: 2.6-2.7.
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure, causing recrystallization. It is found in mountain belts and areas of regional metamorphism globally.
Uses & applications
Used as a crushed stone for road construction, railroad ballast, and building stone. High-purity quartzite is used to produce ferrosilicon, industrial silica sand, and silicon metal. It is also a popular material for kitchen countertops.
Geological facts
Quartzite is so tough that it often survives intense weathering better than other rocks, frequently capping hills and ridges. It is often confused with marble, but can be distinguished because quartzite will scratch glass and marble will not.
Field identification & locations
Identify by its extreme hardness and granular, sugary appearance on freshly broken surfaces. Common in eroded riverbeds or mountainous regions with high metamorphic activity.
More like this
