gemstone

Black onyx or black spinel ring stone

Likely chalcedony (SiO₂), variety black onyx; possibly synthetic spinel or glass

AI-generated identification · may be incorrect

Opaque black, vitreous to waxy luster, no visible crystal faces; onyx/chalcedony hardness ~6.5–7 Mohs, while spinel is ~8. The gold-colored setting appears metal, and the stone may be polished or treated.

Identified August 20, 2026More gemstone →

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At a glance

Common name: Black onyx or black spinel ring stone
Scientific name: Likely chalcedony (SiO₂), variety black onyx; possibly synthetic spinel or glass
Category: gemstone
Identified: August 20, 2026
Method: Standard

AI Estimated Value

Approximately $20–$150 for a common fashion ring; $150–$800+ if solid gold with authenticated natural gemstone, depending on metal weight, craftsmanship, and condition.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Black onyx forms when silica-rich groundwater deposits layered chalcedony in cavities, commonly in volcanic rocks; spinel crystallizes in metamorphic rocks. The image cannot establish geological age or definitively distinguish natural stone from synthetic material.

Uses & applications

Used in signet rings, beads, carvings, and ornamental jewelry; black onyx is generally more affordable than natural black spinel. The setting may be gold, gold-filled, or plated metal.

Geological facts

Uniformly deep black stones in commercial rings are often dyed chalcedony, synthetic spinel, or glass rather than naturally black onyx. A loupe, hardness testing, refractive index, and specific gravity are needed for confirmation.

Field identification & locations

Common sources of onyx include Brazil, India, Mexico, Uruguay, and Pakistan; spinel is associated with Myanmar, Sri Lanka, Tanzania, and Vietnam. Look for banding, uneven color, inclusions, and a glass-like appearance, but avoid scratch testing a finished ring.