mineral
Tumbled quartz-rich stone, possibly milky quartz or calcite
Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing
AI-generated identification · may be incorrectSmall beige-white, opaque, rounded specimen with dull to slightly waxy luster and irregular fractures. Quartz hardness is 7, vitreous, hexagonal; calcite hardness is 3, rhombohedral cleavage, and effervesces in dilute acid.
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Physical properties
Small beige-white, opaque, rounded specimen with dull to slightly waxy luster and irregular fractures. Quartz hardness is 7, vitreous, hexagonal; calcite hardness is 3, rhombohedral cleavage, and effervesces in dilute acid.
Formation & geological history
Likely a naturally weathered or tumbled fragment from a quartz vein, limestone, or mixed sediment; age cannot be determined visually. Quartz forms in hydrothermal veins and igneous/metamorphic rocks, while calcite commonly forms in sedimentary limestones and veins.
Uses & applications
Common quartz is used in glass, ceramics, abrasives, electronics, and collecting; calcite is used in cement, lime, construction aggregate, and optics. This small piece has negligible commercial value.
Geological facts
The strongest distinction is a scratch test: quartz scratches glass, whereas calcite does not. A drop of dilute hydrochloric acid or vinegar may visibly fizz on calcite, but not quartz.
Field identification & locations
Common worldwide; inspect for glass-scratching ability, acid reaction, cleavage, and powder color. The image alone is insufficient for confident species identification.
