mineral

Likely tumbled brown agate or jasper

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

AI-generated identification · may be incorrect

Small rounded, polished specimen with brown-gray coloration and possible subtle banding; vitreous to waxy luster, hardness about 6.5–7 Mohs, no visible cleavage, and specific gravity near 2.6. The blurred image prevents reliable identification of crystal structure or pattern.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Agate and jasper form when silica-rich groundwater fills cavities or fractures in volcanic rocks, commonly during the Cenozoic and older geologic periods. Slow deposition produces chalcedony layers and iron-oxide brown coloration.

Uses & applications

Used as an inexpensive lapidary stone for cabochons, beads, carvings, and tumbled stones; also collected as a decorative specimen.

Geological facts

Agate is translucent and commonly banded, whereas jasper is generally opaque and more uniformly colored; the specimen may be either or a mixture of both.

Field identification & locations

Test for glassy hardness by attempting to scratch glass, though this can damage the specimen; inspect under strong light for translucency and bands. Common sources include Brazil, Uruguay, India, Madagascar, Mexico, and the western United States.