metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: typically white, gray, or pinkish; Luster: vitreous to waxy; Structure: non-foliated, granular texture of interlocking quartz crystals; Cleavage: none; Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- typically white, gray, or pinkish
- Luster
- vitreous to waxy
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: typically white, gray, or pinkish; Luster: vitreous to waxy; Structure: non-foliated, granular texture of interlocking quartz crystals; Cleavage: none; Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the regional or contact metamorphism of quartzose sandstone where high heat and pressure cause the grains to recrystallize and fuse.
Uses & applications
Used as crushed stone in construction, road ballast, dimension stone for kitchen countertops and flooring, and occasionally as a source of silica for glass manufacturing.
Geological facts
Quartzite is so tough that it often forms the caprock or ridges of mountain ranges because it resists weathering better than surrounding rocks; it is much harder than the sandstone it originates from.
Field identification & locations
Identify in the field by its hardness (will easily scratch glass) and its tendency to break across quartz grains rather than around them. It is ubiquitous in metamorphic belts globally, such as the Appalachian Mountains.
More like this
