gemstone
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Colorless/Transparent
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed in igneous, metamorphic, and sedimentary environments, primarily through hydrothermal activity and the cooling of silica-rich magma or hot fluids in veins and cavities throughout geological time.
Uses & applications
Widely used in jewelry making, lapidary carvings, glass manufacturing, electronics (due to piezoelectric properties), and as decorative display specimens.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Historically, clear quartz was believed to be permanently frozen ice by ancient Greeks (hence the name 'krystallos').
Field identification & locations
Identify by its ability to scratch glass (hardness 7), lack of cleavage, and transparent clarity. It is found globally, with significant deposits in Brazil, Madagascar, and Arkansas, USA.
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