mineral
Milky Quartz (Common Quartz/Crystalline Quartz)
Quartz (Silicon Dioxide, SiO2)
Hardness: 7 on Mohs scale; Color: White, tan, or opaque yellowish due to iron staining; Luster: Vitreous (glassy) to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- White, tan, or opaque yellowish due to iron staining
- Luster
- Vitreous (glassy) to greasy
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Physical properties
Hardness: 7 on Mohs scale; Color: White, tan, or opaque yellowish due to iron staining; Luster: Vitreous (glassy) to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
Formation & geological history
Formed through the cooling of silica-rich magma or from hydrothermal veins. The 'milky' appearance is caused by tiny gas-liquid inclusions trapped during crystal growth. Can be found in geological formations of any age, particularly within pegmatites and metamorphic veins.
Uses & applications
Used in the glass and ceramics industry, as a flux in metallurgy, and as a component in concrete. In jewelry, it is used for cabochons or carving. It is also used in the semiconductor industry and for making sandpaper/abrasives.
Geological facts
Quartz is one of the most abundant minerals in the Earth's crust. Ancient Greeks named it 'krustallos' meaning ice, believing it was ice so permanently frozen that it would never melt. High-purity quartz is essential for the production of silicon wafers in electronics.
Field identification & locations
Identify in the field by its inability to be scratched by steel, lack of cleavage, and its waxy/glassy look on fresh breaks. It is ubiquitous worldwide but commonly found in gravel pits, mountain ranges, and near volcanic sites. For collectors, look for large, well-terminated crystals.
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Mineral
Nephrite Jade
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Mineral/Rock
Granite
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