mineral

Agate (chalcedony), likely a cut nodule

Agate, a banded variety of microcrystalline quartz (SiO₂); associated iron oxides stain the rough outer matrix.

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; gray to brown, waxy-to-vitreous luster, cryptocrystalline structure, and no cleavage. The smooth interior shows subtle curved bands and conchoidal fracture.

Identified October 2, 2026More mineral →

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At a glance

Common name: Agate (chalcedony), likely a cut nodule
Scientific name: Agate, a banded variety of microcrystalline quartz (SiO₂); associated iron oxides stain the rough outer matrix.
Category: mineral
Identified: October 2, 2026
Method: Standard

AI Estimated Value

Approximately $10–$60 USD for a common hand-sized slice; stronger banding, unusual colors, or larger size can increase value.

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

Mohs hardness 6.5–7; gray to brown, waxy-to-vitreous luster, cryptocrystalline structure, and no cleavage. The smooth interior shows subtle curved bands and conchoidal fracture.

Formation & geological history

Silica-rich fluids deposited microscopic quartz in cavities, commonly in volcanic rocks; the iron-stained exterior is weathered host material. Agates form across many geological ages, often in ancient lava flows.

Uses & applications

Used for ornamental slabs, jewelry, carvings, and collected specimens; historically also used for small tools and beads.

Geological facts

Agate is chalcedony, not a single large-crystal variety of quartz; its banding records successive silica deposition.

Field identification & locations

Look for waxy translucence, curved banding, and shell-like fracture; common sources include Brazil, Uruguay, India, and volcanic regions worldwide. This appears to be a sawn or polished section with a rough natural rind.