mineral

Weathered quartz-rich nodule, possibly agate or chalcedony

Microcrystalline quartz (SiO₂), potentially with iron-oxide staining or a druzy coating

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray-white, opaque to slightly translucent, with a dull to waxy luster and irregular/conchoidal fracture. The rounded shape and rough pale rim suggest natural weathering or an outer rind; crystal structure is trigonal quartz, though microscopic crystals may appear massive.

Identified August 29, 2026More mineral →

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At a glance

Common name: Weathered quartz-rich nodule, possibly agate or chalcedony
Scientific name: Microcrystalline quartz (SiO₂), potentially with iron-oxide staining or a druzy coating
Category: mineral
Identified: August 29, 2026
Method: Standard

AI Estimated Value

Approximately $1–$10 as an ordinary pebble; $10–$50 if attractive, unusually patterned, or confirmed as quality agate.

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

Likely formed when silica-rich fluids filled a cavity or replaced material in volcanic rock, then weathered free; exact age and type cannot be confirmed from the photograph. It may also be a rounded quartz/chalcedony pebble.

Uses & applications

Common material for lapidary cutting, cabochons, beads, and decorative specimens; ordinary pieces have little industrial or jewelry value.

Geological facts

Agate and chalcedony are varieties of microcrystalline quartz, often showing banding or botryoidal surfaces. A glassy streak, hardness sufficient to scratch ordinary glass, and lack of metallic response support quartz rather than slag or metal ore.

Field identification & locations

Common in volcanic terrains, stream gravels, and desert alluvial deposits worldwide. Test carefully with a steel file or glass, inspect for banding under magnification, and avoid destructive tests if collectible.