mineral

Polished agate/jasper nodule

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide impurities

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent honey-brown to olive-yellow color, waxy to glassy luster, and irregular curved/conchoidal fractures. The rounded, polished surface reveals cloudy chalcedony and possible brecciation or flow-like banding; no visible cleavage.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater filled cavities in volcanic rock, later incorporating iron oxides that produced the yellow-brown coloration. Such agates and jasper-like chalcedony commonly formed during volcanic activity from the Cenozoic to older geologic periods.

Uses & applications

Used as a decorative stone, cabochon, carving, paperweight, and lapidary specimen; generally unsuitable for structural construction.

Geological facts

Agate is a variety of chalcedony whose colors and bands result from repeated silica deposition and trace impurities. The specimen may be sold as “honey agate,” “yellow jasper,” or polished chalcedony, but exact naming requires testing.

Field identification & locations

Identify by its glassy/waxy luster, hardness, translucent edges, and resistance to scratching by steel; acid causes no fizz. Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States.