mineral
Milky quartz
Quartz (SiO₂), likely massive milky quartz
AI-generated identification · may be incorrectWhite, translucent to opaque, with a vitreous-to-pearly luster and no visible cleavage; hardness Mohs 7, trigonal crystal structure, and specific gravity about 2.65. The rough, granular fracture surface is consistent with quartz, though calcite is a possible look-alike.
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Physical properties
White, translucent to opaque, with a vitreous-to-pearly luster and no visible cleavage; hardness Mohs 7, trigonal crystal structure, and specific gravity about 2.65. The rough, granular fracture surface is consistent with quartz, though calcite is a possible look-alike.
Formation & geological history
Forms when silica-rich hydrothermal fluids crystallize in fractures and cavities, or as quartz veins in igneous and metamorphic rocks; specimens may range from Precambrian to recent geological settings. Its cloudy appearance results from microscopic fluid inclusions, fractures, or impurities.
Uses & applications
Used as a silica source in glass, ceramics, foundry materials, and engineered stone; attractive pieces are collected or occasionally cut for cabochons and carvings.
Geological facts
Quartz is one of Earth’s most abundant minerals and is piezoelectric. Milky quartz commonly occurs alongside feldspar, mica, gold, and other vein minerals.
Field identification & locations
Common in quartz veins, granites, pegmatites, and metamorphic terrains worldwide. It scratches glass, lacks cleavage, and typically does not fizz in dilute hydrochloric acid; a hardness or acid test can distinguish it from calcite.
