sedimentary
Yellow Onyx (Commercial Trade Name)
Banding Calcite / Travertine (CaCO3)
AI-generated identification · may be incorrectMohs hardness of 3, vitreous to waxy luster, trigonal crystal system, exhibits distinct color banding in golden, white, and brown tones.
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Physical properties
Mohs hardness of 3, vitreous to waxy luster, trigonal crystal system, exhibits distinct color banding in golden, white, and brown tones.
Formation & geological history
Formed through the precipitation of calcium carbonate in limestone caves, hot springs, or streams over thousands of years.
Uses & applications
Widely used for decorative objects, carved spheres, interior architectural tiles, and high-end countertops.
Geological facts
Often commercially marketed as onyx, true geological onyx is actually a banded chalcedony, whereas this specimen is a banded form of calcite or aragonite.
Field identification & locations
Easily identified by its soft nature (easily scratched by a knife) and strong effervescence when tested with dilute hydrochloric acid.
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