metamorphic
Quartzite (or Pink Quartz)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Pinkish-red to tan; Luster: Vitreous to waxy; Structure: Crystalline/Granular; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6 - 2.7.
- Hardness
- 7 on Mohs scale
- Color
- Pinkish-red to tan
- Luster
- Vitreous to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: Pinkish-red to tan; Luster: Vitreous to waxy; Structure: Crystalline/Granular; 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, often during mountain-building events. The pink color typically comes from trace amounts of iron oxides (hematite).
Uses & applications
Used as crushed stone for road construction, railway ballast, and in the production of glass and industrial silica. High-quality pink specimens are used for ornamental stones, landscaping, and lapidary work.
Geological facts
Quartzite is so durable that it often outlasts the surrounding softer rocks, forming prominent ridges and hills. It is often confused with marble, but can be distinguished because quartzite will not react to acid and is much harder than steel.
Field identification & locations
Identify by its ability to scratch glass easily and its lack of visible grains (unlike the sandstone it originated from). It is found globally in metamorphic belts, such as the Appalachian Mountains in the US or the Precambrian shields of Brazil and Africa.
