mineral

Polished agate or jasper cabochon (uncertain)

Microcrystalline quartz, SiO₂ (likely chalcedony/agate or jasper)

AI-generated identification · may be incorrect

The foreground piece is a polished, flattened brown-black specimen with a smooth waxy-to-glassy luster and possible fine banding or brecciated texture. Quartz varieties have Mohs hardness 6.5–7, no cleavage, conchoidal fracture, and specific gravity about 2.6; exact identification requires close inspection or testing.

Identified September 3, 2026More mineral →

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Physical properties

Formation & geological history

Chalcedony and jasper form when silica-rich groundwater fills cavities or fractures, commonly in volcanic rocks; ages range from recent deposits to Precambrian. The visible polish indicates human processing.

Uses & applications

Used for cabochons, beads, ornaments, and decorative objects; quality depends on pattern, color, polish, and size.

Geological facts

Agate is translucent and commonly banded, whereas jasper is generally opaque and iron-rich; this image may also show a polished iron-stained agate or jasper fragment.

Field identification & locations

Likely locations include volcanic terrains in Brazil, Uruguay, Mexico, India, Madagascar, and the western United States. Check translucency, quartz hardness, and absence of metallic streak; a glass-scratch test can help, though it may damage the specimen.