Rock Identifier
Tumbled red jasper (Microcrystalline quartz (SiO₂), commonly colored by iron oxides) — mineral
mineral

Tumbled red jasper

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

AI-generated identification · may be incorrect

Opaque reddish-brown, fine-grained, matte to weakly waxy luster, with no visible cleavage; Mohs hardness about 6.5–7 and specific gravity roughly 2.5–2.7. The rounded shape and smooth surface indicate mechanical tumbling or water-worn polishing.

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Physical properties

Opaque reddish-brown, fine-grained, matte to weakly waxy luster, with no visible cleavage; Mohs hardness about 6.5–7 and specific gravity roughly 2.5–2.7. The rounded shape and smooth surface indicate mechanical tumbling or water-worn polishing.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron oxides producing the red color; deposits range from Precambrian to younger ages. This specimen is likely commercially tumbled rather than naturally shaped.

Uses & applications

Used as an ornamental stone for cabochons, beads, carvings, countertops, and lapidary pieces; common tumbled specimens have modest value.

Geological facts

Jasper is a variety of chalcedony or microcrystalline quartz, though some material contains abundant non-quartz impurities. Red coloration typically reflects hematite or related iron oxides.

Field identification & locations

Identify it by its opaque brick-red color, very fine texture, hardness sufficient to scratch glass, and absence of cleavage; it should not fizz in dilute acid. Common sources include India, Madagascar, Brazil, Uruguay, and the western United States.