Rock Identifier
Milky quartz-rich rock (Quartz (SiO₂), likely massive milky quartz with minor iron-stained gangue) — mineral
mineral

Milky quartz-rich rock

Quartz (SiO₂), likely massive milky quartz with minor iron-stained gangue

AI-generated identification · may be incorrect

White to translucent, vitreous-to-waxy luster, irregular fracture, and no obvious cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The rusty brown areas likely reflect iron-oxide staining or attached host rock.

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Physical properties

White to translucent, vitreous-to-waxy luster, irregular fracture, and no obvious cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The rusty brown areas likely reflect iron-oxide staining or attached host rock.

Formation & geological history

Quartz crystallized from silica-rich hydrothermal fluids or pegmatitic veins, commonly during Precambrian to younger mountain-building events; the exact age cannot be determined from the image. Its massive, opaque appearance suggests interlocking quartz rather than well-formed crystals.

Uses & applications

Used as a silica source for glass, ceramics, engineered stone, and abrasives; attractive pieces may be collected or polished, though this specimen appears primarily suitable as a field specimen.

Geological facts

Milky quartz gets its cloudiness from microscopic fluid inclusions, fractures, or impurities. It can resemble white calcite, but quartz is harder and will scratch glass.

Field identification & locations

Common in quartz veins, granites, pegmatites, and metamorphic rocks worldwide, including Brazil, the United States, Madagascar, and the Alps. Test with a steel file or glass-scratch test; acid fizzing would instead suggest calcite.