Rock Identifier
Polished yellow-brown jasper (Jasper, a microcrystalline variety of quartz (SiO₂), commonly containing iron-oxide impurities) — mineral
mineral

Polished yellow-brown jasper

Jasper, a microcrystalline variety of quartz (SiO₂), commonly containing iron-oxide impurities

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; mustard to honey-brown color, opaque, with a vitreous-to-waxy polish and no visible cleavage. Its cryptocrystalline quartz structure gives a dense, smooth texture and typical specific gravity near 2.6.

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Physical properties

Hardness about 6.5–7 Mohs; mustard to honey-brown color, opaque, with a vitreous-to-waxy polish and no visible cleavage. Its cryptocrystalline quartz structure gives a dense, smooth texture and typical specific gravity near 2.6.

Formation & geological history

Forms when silica-rich fluids replace or cement fine-grained sediments or volcanic material, with iron producing the brown-yellow coloration. Deposits formed in many geological periods, commonly in volcanic and sedimentary environments.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and decorative objects; occasionally used as ornamental facing stone. Common polished pieces generally have modest collector value.

Geological facts

Jasper is technically a rock rather than a single pure mineral because it contains microcrystalline quartz plus impurities. Color and pattern names are often commercial rather than strict geological classifications.

Field identification & locations

Common in India, Madagascar, Brazil, Australia, South Africa, and the western United States. Identify it by opacity, fine grain, lack of cleavage, glass-scratching hardness, and an earthy iron-rich color; this specimen appears tumbled and polished.