mineral
Milky quartz specimen
Quartz (silicon dioxide, SiO₂)
AI-generated identification · may be incorrectWhite to translucent, vitreous-to-pearly luster with irregular fracture and no obvious cleavage; Mohs hardness 7, trigonal crystal structure, and specific gravity about 2.65. The brown areas are likely iron-oxide staining or attached host material.
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Physical properties
White to translucent, vitreous-to-pearly luster with irregular fracture and no obvious cleavage; Mohs hardness 7, trigonal crystal structure, and specific gravity about 2.65. The brown areas are likely iron-oxide staining or attached host material.
Formation & geological history
Quartz commonly crystallizes from silica-rich hydrothermal fluids, pegmatites, and cavities in igneous or metamorphic rocks; its age depends on the host formation and may range from Precambrian to recent. This appears to be a natural, uncut fragment.
Uses & applications
Used in glass, ceramics, foundry materials, electronics, abrasives, and engineered stone; attractive pieces are collected but generally have limited gemstone value.
Geological facts
Milky quartz is cloudy because microscopic fluid inclusions, fractures, or mineral impurities scatter light. It is often confused with calcite, but quartz is significantly harder and does not effervesce in dilute hydrochloric acid.
Field identification & locations
Common worldwide, including Brazil, Madagascar, the United States, and alpine or granitic regions. Scratch testing with care—quartz should scratch glass, while a steel blade should not scratch it; avoid damaging the specimen.
