mineral
Polished banded calcite (onyx marble)
Calcite, CaCO₃; commonly sold as banded calcite or “onyx marble”
AI-generated identification · may be incorrectCream to pale yellow, with curved, layered bands and a polished vitreous-to-waxy luster; calcite has Mohs hardness 3, trigonal crystal structure, and perfect rhombohedral cleavage. The image does not allow reliable confirmation of the material.
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Physical properties
Cream to pale yellow, with curved, layered bands and a polished vitreous-to-waxy luster; calcite has Mohs hardness 3, trigonal crystal structure, and perfect rhombohedral cleavage. The image does not allow reliable confirmation of the material.
Formation & geological history
Forms as calcite precipitates from mineral-rich water in caves, springs, or veins, building up successive bands; its age depends on the deposit.
Uses & applications
Carved and polished into decorative objects, beads, and ornamental stone; softer than quartz gemstones and not ideal for wear-intensive jewelry.
Geological facts
“Onyx marble” is a trade name for banded calcite and is not true onyx, which is banded chalcedony.
Field identification & locations
Look for pale curved bands, low hardness, and vigorous fizzing with dilute acid; common deposits occur in Mexico, Pakistan, and parts of the United States. A photo alone cannot distinguish it confidently from other pale banded stones.
