mineral

Black Onyx and Mother of Pearl

Cryptocrystalline Quartz (SiO2) and Nacre (Calcium Carbonate)

AI-generated identification · may be incorrect

Black beads: Hardness 6.5-7, vitreous luster, opaque black color. White pieces: Hardness 3.5, pearly luster, iridescent white color, monoclinic/hexagonal structures.

Identified July 20, 2026More mineral →

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Physical properties

Black beads: Hardness 6.5-7, vitreous luster, opaque black color. White pieces: Hardness 3.5, pearly luster, iridescent white color, monoclinic/hexagonal structures.

Formation & geological history

Onyx forms in gas cavities of lava; Mother of Pearl is organic-mineral material produced by mollusks as an inner shell layer.

Uses & applications

Primarily used in jewelry, decorative carvings, and ornamental lapidary work.

Geological facts

Black onyx in the market is often high-quality gray chalcedony that has been dyed to achieve its uniform black color, a practice used since ancient Roman times.

Field identification & locations

Identify Onyx by its hardness and waxy to vitreous luster; Mother of Pearl by its characteristic 'orient' or iridescent play of light. Found globally in volcanic or marine environments.