mineral

Green Onyx (Banded Calcite)

Calcite (Calcium Carbonate, CaCO3)

Hardness: 3 on Mohs scale; Color: Pale green to apple green with white/tan banding; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: Pale green to apple green with white/tan banding
Luster: Vitreous to waxy

Identified May 3, 2026More mineral →

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Physical properties

Hardness: 3 on Mohs scale; Color: Pale green to apple green with white/tan banding; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71

Formation & geological history

Formed by the precipitation of calcium carbonate from cold water springs or limestone caves, creating layered deposits known as travertine or Mexican Onyx. Most commercial green specimens come from modern geological formations.

Uses & applications

Extensively used for ornamental carvings, figurines, bookends, interior decorative tiling, and jewelry as pendants or beads.

Geological facts

Despite being marketed as 'Green Onyx,' it is geologically a form of calcite or aragonite, not true chalcedony onyx. It is prized for its translucent quality when sliced thin.

Field identification & locations

Identify by its softness (can be scratched by a copper penny or steel knife) and the presence of parallel layers or banding. Often found in Pakistan, Mexico, and Iran. Collectors look for clarity and vibrant green hues.

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