gemstone
Faceted Quartz (Rock Crystal)
Crystalline Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Fracture: Conchoidal; Specific Gravity: 2.65.
- 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; Fracture: Conchoidal; Specific Gravity: 2.65.
Formation & geological history
Forms in a wide range of geological environments, most notably from cooling silica-rich magma in igneous rocks like granite or from hydrothermal veins. This specific specimen has been human-processed with machine-cut facets.
Uses & applications
Used extensively in jewelry as a gemstone, in crystal healing practices, as decorative home decor, and in industrial optics or electronics.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Pure colorless quartz is known as 'Rock Crystal' and was once believed by ancient Greeks to be ice that had frozen so hard it would never melt.
Field identification & locations
Identified by its ability to scratch glass (hardness 7) and its lack of cleavage. As a faceted piece, look for crisp edges and a lack of bubbles (which would indicate glass). It is found globally, with major deposits in Brazil and Arkansas, USA.
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