metamorphic
Quartzite
Metamorphic Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: White, gray, pink, or reddish; Luster: Vitreous to greasy; Crystal structure: Massive, interlocking quartz grains; Cleavage: None (fractures conchoidally); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- White, gray, pink, or reddish
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 on Mohs scale; Color: White, gray, pink, or reddish; Luster: Vitreous to greasy; Crystal structure: Massive, interlocking quartz grains; Cleavage: None (fractures conchoidally); Specific gravity: 2.65
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under high heat and tectonic pressure, commonly over hundreds of millions of years.
Uses & applications
Used in construction, as road aggregate, railroad ballast, manufacturing of silica brick, and occasionally for decorative landscaping or countertops.
Geological facts
Because quartz is extremely resistant to weathering, quartzite ridges often stand out as prominent hills or ridges in a landscape. The provided location in the Greater Caucasus region features complex metamorphic and sedimentary formations where quartzites and related rocks are locally common.
Field identification & locations
Can be identified in the field by its extreme hardness (scratches glass easily, cannot be scratched by a knife) and the lack of visible separate grains breaking apart—it fractures through the grains rather than around them.
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