igneous
Quartz vein rock (milky quartz)
Milky quartz, SiO₂; likely quartz-rich vein material in altered host rock
AI-generated identification · may be incorrectWhite to gray, translucent-to-opaque quartz with a vitreous-to-waxy luster; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The specimen appears massive and fractured, with minor dark mineral or host-rock inclusions.
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Physical properties
White to gray, translucent-to-opaque quartz with a vitreous-to-waxy luster; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The specimen appears massive and fractured, with minor dark mineral or host-rock inclusions.
Formation & geological history
Quartz precipitated from hot, silica-rich hydrothermal fluids filling fractures, commonly during cooling and alteration of surrounding igneous or metamorphic rocks. The exact geological age cannot be determined from the photograph.
Uses & applications
Common quartz is used in glass, ceramics, abrasives, foundry materials, and engineered stone; attractive pieces are collected or used decoratively. This rough material has little jewelry value unless unusually clear or aesthetically patterned.
Geological facts
Milky appearance results mainly from microscopic fluid inclusions, fractures, and impurities scattering light. Quartz is one of Earth’s most abundant and chemically durable minerals.
Field identification & locations
Identify it by its hardness— it should scratch ordinary glass—and lack of cleavage, unlike calcite, which fizzes in acid and is much softer. Common worldwide in hydrothermal veins, pegmatites, and metamorphic terrains.
