gemstone

Black onyx and orange agate beads

Onyx (banded chalcedony, SiO₂) and orange chalcedony/agate (SiO₂); the orange color may be enhanced by dye or heat treatment

AI-generated identification · may be incorrect

Both are microcrystalline quartz, Mohs hardness 6.5–7, with a vitreous to waxy luster and no visible cleavage. The black beads appear opaque and polished; the orange beads are translucent and may show color treatment.

Identified October 2, 2026More gemstone →

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Physical properties

Formation & geological history

Chalcedony forms as silica precipitates in cavities and fractures, commonly in volcanic rocks; banding develops as silica layers accumulate. These beads are cut and polished from geological material; the image does not establish their age or treatment.

Uses & applications

Used in jewelry, especially bead necklaces and bracelets, and as decorative or collectible lapidary material.

Geological facts

Commercial “black onyx” is often uniformly colored chalcedony, sometimes dyed; true onyx typically has parallel bands. Orange agate is also commonly dyed to intensify its color.

Field identification & locations

Identify by the smooth, polished surface and glassy/waxy luster; inspect for natural bands or color concentrated in cracks. Chalcedony occurs worldwide, including Brazil, India, and the United States.