mineral
Likely banded calcite (possibly satin spar gypsum)
Calcite (CaCO₃); alternatively gypsum, CaSO₄·2H₂O
AI-generated identification · may be incorrectA silvery-gray, fibrous-looking piece with tan bands and pearly to silky luster. If calcite, hardness 3 Mohs with rhombohedral cleavage; if gypsum, hardness 2 with one perfect cleavage. The image alone does not distinguish them confidently.
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Physical properties
A silvery-gray, fibrous-looking piece with tan bands and pearly to silky luster. If calcite, hardness 3 Mohs with rhombohedral cleavage; if gypsum, hardness 2 with one perfect cleavage. The image alone does not distinguish them confidently.
Formation & geological history
May have formed as a banded vein or cave deposit from mineral-rich water; age and exact origin cannot be determined from the photo.
Uses & applications
Calcite is used in cement, lime, and ornamental objects; satin spar gypsum is used for carvings and decorative pieces.
Geological facts
Both minerals can form striking fibrous or banded specimens, and visual appearance can overlap substantially.
Field identification & locations
Check hardness cautiously: gypsum is easily scratched by a fingernail, while calcite is not; calcite also fizzes in dilute acid. Common worldwide in sedimentary rocks, veins, and caves.
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