mineral

Likely quartz-rich mineral fragment

Quartz (SiO₂), possibly a small piece of milky quartz or calcite

AI-generated identification · may be incorrect

White, translucent, and irregular with a dull-to-glassy luster; hardness is likely 7 if quartz, or 3 if calcite. Crystal structure cannot be confirmed from the image; apparent granular texture may indicate a broken crystal or aggregate.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Quartz commonly forms in hydrothermal veins, igneous rocks, and metamorphic environments; calcite commonly forms in limestone and mineral veins. A specimen’s geological age cannot be determined visually.

Uses & applications

Quartz is used in glass, electronics, abrasives, and collecting; calcite is used in cement, aggregate, and optical specimens. This fragment has little commercial value unless it proves to be a notable crystal.

Geological facts

Quartz does not fizz in dilute hydrochloric acid and scratches glass; calcite fizzes and is easily scratched with a steel knife. The image alone is insufficient for confident species identification.

Field identification & locations

Commonly found worldwide, including Brazil, the United States, Mexico, and China. Test hardness, streak, transparency, and acid reaction; avoid acid testing if the specimen may be valuable.