mineral

Tumbled chalcedony (likely yellow agate or citrine-like quartz)

Microcrystalline quartz, SiO₂; yellow coloration may result from iron oxides or inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent yellow to gray, waxy-to-glassy luster, cryptocrystalline structure, and no visible cleavage. The rounded shape indicates tumbling or water wear.

Identified August 22, 2026More mineral →

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At a glance

Common name: Tumbled chalcedony (likely yellow agate or citrine-like quartz)
Scientific name: Microcrystalline quartz, SiO₂; yellow coloration may result from iron oxides or inclusions
Category: mineral
Identified: August 22, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small common tumbled piece; $20–$100+ if strongly patterned, naturally vivid, or fashioned as quality jewelry.

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

Hardness 6.5–7 Mohs; translucent yellow to gray, waxy-to-glassy luster, cryptocrystalline structure, and no visible cleavage. The rounded shape indicates tumbling or water wear.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rock, precipitating microscopic quartz layers; coloration commonly develops from iron-bearing impurities. Deposits occur in many Cenozoic and older volcanic terrains.

Uses & applications

Used for cabochons, carvings, beads, decorative stones, and lapidary practice; ordinary pieces have modest ornamental value.

Geological facts

Chalcedony is quartz whose crystals are too small to see unaided; agate is a banded or patterned variety. A true citrine would generally show more transparent, crystalline quartz texture.

Field identification & locations

Identify by its hardness, waxy appearance, translucency, conchoidal fracture, and inability to scratch it with a steel knife; it should scratch glass. Common sources include Brazil, Uruguay, India, Mexico, and the United States.