mineral

Polished agate or jasper fragment

Microcrystalline quartz (chalcedony), SiO₂, possibly iron-oxide-rich

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; reddish-brown, cream, and gray coloration with a dull to waxy luster. The irregular cut/polished surface and fine-grained texture suggest cryptocrystalline quartz, though details are insufficient for confident identification.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater filled cavities in volcanic rock, with iron oxides producing red-brown coloration; commonly Cenozoic to older, depending on source locality. It appears human-cut or tumbled rather than naturally weathered.

Uses & applications

Used for cabochons, carvings, beads, ornamental objects, and inexpensive lapidary specimens; not generally used as construction stone in this small form.

Geological facts

Agate and jasper are varieties of chalcedony distinguished largely by appearance: agate commonly shows banding or translucency, while jasper is more opaque and opaque iron-rich red material.

Field identification & locations

Look for a glassy or waxy surface, conchoidal fracture, absence of visible large crystals, and resistance to scratching glass; a steel blade should not scratch it easily. Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States.