mineral
Milky quartz-rich rock
Quartz (SiO₂), likely massive quartz with iron-oxide staining and minor feldspar or mica
AI-generated identification · may be incorrectWhite to pale gray, opaque to translucent, with a vitreous-to-waxy luster and irregular fracture; individual crystal faces are not obvious. Quartz has Mohs hardness 7, no cleavage, hexagonal crystal structure, and specific gravity about 2.65.
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Physical properties
White to pale gray, opaque to translucent, with a vitreous-to-waxy luster and irregular fracture; individual crystal faces are not obvious. Quartz has Mohs hardness 7, no cleavage, hexagonal crystal structure, and specific gravity about 2.65.
Formation & geological history
Likely formed when silica-rich hydrothermal fluids filled a fracture, producing a quartz vein; the rusty peach coloration probably reflects iron-oxide weathering. Exact geological age cannot be determined from the photograph.
Uses & applications
Common quartz is used in glass, ceramics, engineered stone, abrasives, and electronics; attractive pieces are collected or used decoratively. This rough specimen has modest commercial value.
Geological facts
Its hardness and lack of cleavage distinguish quartz from calcite and many feldspars. A steel knife should not scratch it, while quartz should scratch ordinary glass.
Field identification & locations
Common in quartz veins, granites, metamorphic rocks, and mineralized fault zones worldwide. Confirm with a streak test (white), hardness test, and—if permitted—acid testing of any suspected calcite coating; avoid confusing surface weathering with mineral identity.
