mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Pale yellowish-brown to grayish-black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Pale yellowish-brown to grayish-black
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale yellowish-brown to grayish-black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in igneous and metamorphic rocks, especially granites and pegmatites. The smoky color is caused by natural irradiation of aluminum-bearing quartz over millions of years.
Uses & applications
Used in gemstone jewelry, ornamental carvings, and electronics (as oscillators). Also popular among collectors and for metaphysical practices.
Geological facts
Smoky Quartz is the national gem of Scotland, where it has been mined since the 1830s in the Cairngorm Mountains and is often called 'Cairngorm stone'.
Field identification & locations
Identify by its hardness (scratches glass), lack of cleavage, and translucent brown to gray hue. Commonly found in mountainous regions with granitic outcrops.
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Mineral/Rock
Banded Gneiss (River Rock/Pebble)
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Metamorphic Rock
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Green Apatite on Albite
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mineral