gemstone

Likely banded agate or chalcedony

Microcrystalline quartz (SiO₂), possibly iron-stained agate

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray, cream, and brown coloration with translucent edges and subtle banding. Waxy to vitreous luster, cryptocrystalline structure, no obvious cleavage, and specific gravity near 2.60–2.65.

Identified September 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rocks, depositing successive layers of chalcedony and quartz; individual specimens may range from Cenozoic to much older depending on host rock.

Uses & applications

Used for cabochons, beads, carvings, polished slices, and ornamental objects; attractive patterned pieces have modest lapidary value.

Geological facts

Agate is a variety of chalcedony distinguished by banding or other internal patterns, while brown coloration commonly results from iron oxides.

Field identification & locations

Look for translucent margins, waxy luster, curved fracture, and fine concentric or mossy banding; common sources include Brazil, Uruguay, Mexico, India, and the western United States. The photograph alone cannot confirm agate versus ordinary chalcedony or jasper.