mineral

Tumbled yellow chalcedony or calcite

Cryptocrystalline quartz (SiO₂), possibly yellow chalcedony; an alternative is yellow calcite (CaCO₃)

AI-generated identification · may be incorrect

Smooth, rounded, cream-yellow, and waxy to weakly vitreous; chalcedony has Mohs hardness 6.5–7 and no cleavage, while calcite is softer (Mohs 3) with rhombohedral cleavage. The opaque, cloudy appearance prevents confident identification from the image alone.

Identified September 15, 2026More mineral →

Explore Tumbled yellow chalcedony or calcite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Tumbled yellow chalcedony or calcite
Scientific name: Cryptocrystalline quartz (SiO₂), possibly yellow chalcedony; an alternative is yellow calcite (CaCO₃)
Category: mineral
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $2–$15 as a common tumbled stone; exceptional natural color or verified gem-quality material may reach $20–$75.

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

Yellow chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; calcite forms from carbonate-rich fluids or sedimentary deposits. Both range from ancient to geologically recent and may be naturally rounded or mechanically tumbled.

Uses & applications

Used as a decorative tumbled stone, cabochon, paperweight, and collector specimen; chalcedony can be used in jewelry, whereas calcite is generally less durable.

Geological facts

A steel knife or glass-scratch test can help distinguish them: chalcedony resists scratching and may scratch glass; calcite scratches easily. Dilute vinegar or acid fizzes on calcite but not chalcedony, though testing can damage the specimen.

Field identification & locations

Common sources include Brazil, Mexico, India, Madagascar, and the United States. Confirm identity with hardness, acid reaction, and ideally specific gravity or microscopy.