metamorphic
Quartzite
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: white to pale pinkish-tan; Luster: vitreous to dull; Crystal Structure: non-foliated, interlocking quartz grains; Cleavage: none (conchoidal fracture); Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- white to pale pinkish-tan
- Luster
- vitreous to dull
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: white to pale pinkish-tan; Luster: vitreous to dull; Crystal Structure: non-foliated, interlocking quartz grains; Cleavage: none (conchoidal fracture); Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone. High heat and pressure causes the original quartz grains to recrystallize and fuse together into a dense, hard rock.
Uses & applications
Used as crushed stone for road construction, railroad ballast, and as a raw material in the glass and ceramics industries. Finer specimens are used for decorative landscaping and interior design.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often forming the peaks of hills and mountain ranges. It is harder than steel and will easily scratch a glass plate.
Field identification & locations
Identify in the field by its extreme hardness, grainy 'sugary' texture, and the way it breaks across the grains rather than around them (unlike sandstone). Commonly found in mountain belts and riverbeds.
More like this
