mineral

Brown chalcedony (likely carnelian/iron-stained quartz)

Microcrystalline quartz, SiO₂; brown coloration from iron oxides/hydroxides

AI-generated identification · may be incorrect

Waxy to resinous luster, translucent brown-orange color, irregular conchoidal fracture, and no visible cleavage; Mohs hardness about 6.5–7, specific gravity approximately 2.60. The rough surface and pale patches may indicate druzy quartz or included host rock.

Identified August 10, 2026More mineral →

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At a glance

Common name: Brown chalcedony (likely carnelian/iron-stained quartz)
Scientific name: Microcrystalline quartz, SiO₂; brown coloration from iron oxides/hydroxides
Category: mineral
Identified: August 10, 2026
Method: Standard

AI Estimated Value

$2–$15 as a rough common specimen; approximately $20–$100 if it polishes well and displays strong translucency or attractive patterning.

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

Forms when silica-rich groundwater fills cavities and fractures, depositing microcrystalline quartz, often with later iron staining. It occurs in volcanic cavities and sedimentary silica deposits, ranging from ancient Precambrian material to much younger formations.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and ornamental objects; attractive polished pieces have modest gemstone value.

Geological facts

Carnelian is the orange-red variety of chalcedony, while darker brown material is commonly called sard or iron-stained chalcedony. Exact identification requires testing because jasper, agate, and resinous slag can look similar.

Field identification & locations

Likely chalcedony if it scratches glass and leaves a white streak; it should not show metallic sparkles or bubbles. Common sources include Brazil, India, Madagascar, Uruguay, and western North America; inspect for natural banding or botryoidal texture.