gemstone

Black polished stone beads, likely black onyx or agate

Likely chalcedony (microcrystalline quartz, SiO₂); exact material cannot be confirmed from the image

AI-generated identification · may be incorrect

Small, opaque-to-translucent, glossy black spherical beads. If chalcedony, hardness is about 6.5–7 Mohs, with a trigonal quartz structure and no cleavage; specific gravity is about 2.6.

Identified October 13, 2026More gemstone →

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At a glance

Common name: Black polished stone beads, likely black onyx or agate
Scientific name: Likely chalcedony (microcrystalline quartz, SiO₂); exact material cannot be confirmed from the image
Category: gemstone
Identified: October 13, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a pair of common loose beads; more if verified natural stone or part of a quality jewelry piece.

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

Small, opaque-to-translucent, glossy black spherical beads. If chalcedony, hardness is about 6.5–7 Mohs, with a trigonal quartz structure and no cleavage; specific gravity is about 2.6.

Formation & geological history

Chalcedony forms as silica deposits in cavities and fractures, often in volcanic rocks; its age depends on the host deposit. The beads have been drilled and polished.

Uses & applications

Used in necklaces, bracelets, and other jewelry; black glass or synthetic materials can look similar.

Geological facts

“Black onyx” jewelry commonly refers to uniformly dark chalcedony, though dyed agate and non-geological imitations are also sold under similar descriptions.

Field identification & locations

The image alone cannot distinguish natural chalcedony from glass or another bead material. Look for natural banding, tiny inclusions, and consistent hardness; a scratch or gemological test is more reliable.