gemstone

Brown agate or chalcedony cabochon pendant

Microcrystalline quartz (SiO₂), likely brown chalcedony/agate

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; opaque to slightly translucent brown, with a waxy-to-glassy luster and no visible cleavage. The smooth domed cabochon and metal setting obscure internal banding or crystal structure.

Identified August 23, 2026More gemstone →

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At a glance

Common name: Brown agate or chalcedony cabochon pendant
Scientific name: Microcrystalline quartz (SiO₂), likely brown chalcedony/agate
Category: gemstone
Identified: August 23, 2026
Method: Standard

AI Estimated Value

Approximately $20–$100 for a typical commercial pendant; $100–$300 or more if the stone is verified high-quality agate/chalcedony and the mount is genuine sterling silver.

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

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; coloration may result from iron or other trace impurities. The specimen is polished and set in jewelry, so its precise geological age and locality cannot be determined visually.

Uses & applications

Used primarily in pendants, cabochons, carvings, and ornamental objects; durable enough for everyday jewelry. The surrounding setting appears to be silver-tone metal, possibly sterling silver, but requires testing.

Geological facts

Brown chalcedony is often marketed as smoky agate, brown agate, or chocolate chalcedony, though trade names are not always mineralogically precise. Lack of visible banding makes exact identification uncertain from the photograph alone.

Field identification & locations

Identify by its fine-grained waxy appearance, high hardness, and absence of cleavage; glass or plastic imitations may show bubbles, seams, or lower hardness. Common sources include Brazil, Uruguay, India, Mexico, Madagascar, and the United States.