metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 (Mohs scale), Color: light grey to tan, Luster: dull to vitreous, Texture: granular and crystalline, Specific Gravity: 2.6-2.7
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Physical properties
Hardness: 7 (Mohs scale), Color: light grey to tan, Luster: dull to vitreous, Texture: granular and crystalline, Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. It undergoes extreme heat and pressure, causing the original quartz grains to recrystallize and fuse into a solid network.
Uses & applications
Mainly used in construction for road ballast, floor tiles, and countertop surfaces; also used as an industrial source of silica.
Geological facts
Quartzite is so hard that it can scratch steel and glass. It is often more resistant to weathering than the surrounding rock, often forming the tops of ridges and hills.
Field identification & locations
Identify in the field by its sugary texture and extreme hardness. It is commonly found in mountain ranges or riverbeds as rounded cobbles due to its durability.
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