mineral
Likely tumbled yellow calcite or aragonite
Calcite (CaCO₃) or aragonite (CaCO₃)
AI-generated identification · may be incorrectSmall polished, pale-yellow translucent specimen with a waxy to pearly luster; calcite has Mohs hardness 3, rhombohedral cleavage, and aragonite hardness 3.5–4. The image lacks enough detail for a definitive distinction.
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Physical properties
Small polished, pale-yellow translucent specimen with a waxy to pearly luster; calcite has Mohs hardness 3, rhombohedral cleavage, and aragonite hardness 3.5–4. The image lacks enough detail for a definitive distinction.
Formation & geological history
Calcium-carbonate minerals form in sedimentary, hydrothermal, cave, and biological environments; aragonite commonly forms in shells and low-temperature deposits. Specimen age cannot be determined from the photograph.
Uses & applications
Used as a decorative or teaching specimen; calcite is important in cement, lime, glass, and agriculture, while aragonite is chiefly ornamental and industrially minor.
Geological facts
Calcite effervesces strongly with dilute hydrochloric acid, whereas aragonite may react more slowly when unpowdered. The irregular bone-like shape appears tumbled or carved rather than naturally crystallized.
Field identification & locations
Common sources include Mexico, the United States, Spain, Morocco, and Namibia. Confirm with a hardness test, streak, and acid reaction; avoid testing valuable specimens visibly.
