mineral
Milky quartz-bearing rock (likely quartz vein fragment)
Quartz, silicon dioxide (SiO₂), with probable iron-oxide staining and dark host-rock inclusions
AI-generated identification · may be incorrectWhite to translucent quartz with vitreous-to-waxy luster, irregular fracture, and no obvious cleavage; Mohs hardness 7, specific gravity about 2.65. The brown-black material is likely limonite/goethite staining or attached altered host rock; crystal form is massive rather than well terminated.
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Physical properties
White to translucent quartz with vitreous-to-waxy luster, irregular fracture, and no obvious cleavage; Mohs hardness 7, specific gravity about 2.65. The brown-black material is likely limonite/goethite staining or attached altered host rock; crystal form is massive rather than well terminated.
Formation & geological history
Likely formed when silica-rich hydrothermal fluids filled fractures in older rock, later weathering to expose the vein fragment. Exact age and host formation cannot be determined from the photograph.
Uses & applications
Common quartz is used in glass, ceramics, abrasives, engineered stone, and electronics; attractive pieces are collected or used decoratively. This specimen appears mainly of modest display value.
Geological facts
Quartz commonly shows conchoidal fracture and can scratch ordinary glass. Iron oxides often create yellow, orange, brown, or reddish coatings and inclusions.
Field identification & locations
Confirm by testing whether it scratches glass but not steel, and by checking for quartz’s lack of cleavage; a streak test should be white. Quartz veins occur worldwide, especially in granitic, metamorphic, and hydrothermal terrains.
