mineral
Quartz (Smoky Quartz / Chalcedony)
Silicon Dioxide (SiO2)
Hardness 7 on Mohs scale, vitreous to waxy luster, trigonal crystal system, conchoidal fracture, white streak, specific gravity ~2.65, translucent brownish-gray to pale violet-gray hue.
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Physical properties
Hardness 7 on Mohs scale, vitreous to waxy luster, trigonal crystal system, conchoidal fracture, white streak, specific gravity ~2.65, translucent brownish-gray to pale violet-gray hue.
Formation & geological history
Formed in igneous, metamorphic, and hydrothermal environments from silica-rich fluids. Can occur as macrocrystalline quartz in pegmatites or microcrystalline chalcedony in sedimentary cavity fillings.
Uses & applications
Used in lapidary art, jewelry making, ornamental carvings, crystal healing, and collected as mineral specimens.
Geological facts
Quartz is one of the most abundant minerals in the Earth's crust. Its varieties include amethyst, citrine, smoky quartz, and agate, determined by trace impurities and natural radiation.
Field identification & locations
Identified by its scratch resistance (scratches glass readily, Mohs 7), lack of cleavage, and distinct conchoidal fracture surfaces. Commonly found worldwide in pegmatites, riverbeds, and gravel deposits.
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