mineral

Polished yellow-brown agate or jasper fragment

Microcrystalline quartz (chalcedony), SiO₂; exact identification is uncertain from the image

AI-generated identification · may be incorrect

Opaque to translucent mustard-brown material with a smooth polished surface and waxy luster; quartz hardness is about Mohs 6.5–7, with no obvious cleavage and conchoidal fracture. The dark banding may indicate iron-rich chalcedony or jasper.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; iron oxides create yellow, brown, and reddish colors. Individual pieces may range from Paleozoic to recent geological settings.

Uses & applications

Used for cabochons, beads, carvings, tumbling, and decorative objects; less commonly as durable ornamental stone.

Geological facts

Agate is banded chalcedony, whereas jasper is more opaque and impure; the specimen may be a cut or tumbled piece rather than a natural crystal.

Field identification & locations

Look for curved/concentric banding, waxy luster, quartz-like hardness, and resistance to scratching by steel; a streak, translucency test, and magnification would help distinguish agate from jasper or dyed material. Common sources include Brazil, Uruguay, India, Madagascar, Mexico, and the western United States.