mineral

Banded agate (likely mossy/chalcedony-rich agate)

Microcrystalline quartz, SiO₂ (chalcedony); bands may include iron oxides and inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent cream, gray, tan, and brown coloration with concentric or flowing banding. Waxy to vitreous luster, cryptocrystalline structure, no cleavage, and typical specific gravity near 2.60.

Identified August 22, 2026More mineral →

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At a glance

Common name: Banded agate (likely mossy/chalcedony-rich agate)
Scientific name: Microcrystalline quartz, SiO₂ (chalcedony); bands may include iron oxides and inclusions
Category: mineral
Identified: August 22, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 as an ordinary rough specimen; $30–$150 or more if cutting reveals attractive, strongly contrasting bands.

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 deposits successive layers of chalcedony in cavities and fractures, commonly in volcanic rocks; iron and other impurities create the brown bands and patches. Individual agates may range from Paleozoic to modern geologic ages.

Uses & applications

Used for cabochons, beads, carvings, bookends, and ornamental slabs; tougher material is also used for burnishing tools and laboratory mortars. This rough specimen has modest value unless cutting reveals exceptional patterning.

Geological facts

Agate is a variety of chalcedony distinguished by banding, and many patterns develop from rhythmic changes in fluid chemistry. Its fine texture allows a high polish.

Field identification & locations

Identify by its waxy surface, translucency, curved banding, and lack of visible large quartz crystals; a steel file should not easily scratch it. Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States.