metamorphic
Red Quartzite
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Reddish-brown due to iron oxide impurities; 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
- Reddish-brown due to iron oxide impurities
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Reddish-brown due to iron oxide impurities; 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 under intense heat and pressure, typically during mountain-building events. The parent sandstone grains recrystallize into a dense mosaic.
Uses & applications
Used as a decorative stone in landscaping, as railway ballast, in construction as crushed stone, and occasionally for making tools or sculptures due to its durability.
Geological facts
Quartzite is so hard that it will scratch glass and steel. It is often more resistant to weathering than the surrounding rock, leading to the formation of prominent ridges and peaks.
Field identification & locations
Identify in the field by its extreme hardness and grainy texture that, unlike sandstone, breaks across the quartz grains rather than around them. Commonly found in folded mountain belts globally.
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