Rock Identifier
Possible tumbled jasper or iron-rich chert (Microcrystalline quartz (SiO₂), variably mixed with iron oxides) — mineral
mineral

Possible tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), variably mixed with iron oxides

AI-generated identification · may be incorrect

Small rounded brown-red specimen with earthy to slightly waxy luster and mottled coloration; likely hardness about 6.5–7 Mohs, no obvious cleavage, and opaque to weakly translucent edges. Exact identification is limited by the image scale and lighting.

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Physical properties

Small rounded brown-red specimen with earthy to slightly waxy luster and mottled coloration; likely hardness about 6.5–7 Mohs, no obvious cleavage, and opaque to weakly translucent edges. Exact identification is limited by the image scale and lighting.

Formation & geological history

Forms when silica-rich fluids replace or cement sediment, with iron oxides producing the brown-red colors; such material commonly formed in ancient sedimentary or volcanic environments, often Precambrian to younger.

Uses & applications

Used as inexpensive lapidary material for cabochons, beads, carvings, and polished stones; usually collected for appearance rather than high monetary value.

Geological facts

Jasper and chert are varieties of microcrystalline quartz and can be difficult to distinguish visually. A steel file should not readily scratch it, while quartz should scratch glass.

Field identification & locations

Common in sedimentary and volcanic terrains worldwide, including the western United States, Brazil, Madagascar, and Australia. A streak test, hardness test, and close inspection for translucent quartz-rich areas would improve identification.