mineral
Smoky Quartz (Polished)
Silicon Dioxide (SiO2)
Hardness 7 on Mohs scale, translucent brownish-gray to dark smoky color, vitreous (glassy) luster, trigonal crystal structure, conchoidal fracture, specific gravity 2.65.
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Physical properties
Hardness 7 on Mohs scale, translucent brownish-gray to dark smoky color, vitreous (glassy) luster, trigonal crystal structure, conchoidal fracture, specific gravity 2.65.
Formation & geological history
Forms in intrusive igneous rocks such as granite and pegmatites, as well as high-temperature hydrothermal veins. Color is derived from natural irradiation of aluminum-bearing quartz.
Uses & applications
Popular as a lapidary material, used for polished gemstones, carvings, beads, tumbled stones, decor, and in crystal healing practices.
Geological facts
Smoky quartz was used in 12th-century China to make early sunglasses. It is the national gem of Scotland, where it is known as Cairngorm.
Field identification & locations
Identified by its signature translucent grey-to-brown color and quartz-like hardness. Common in granite regions globally (e.g., Brazil, USA, Madagascar).
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