mineral

Polished ocean jasper (orbicular jasper)

Jasper, microcrystalline quartz (SiO₂), commonly with iron oxides and chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown, cream, and reddish coloration with earthy to silky luster. It is cryptocrystalline, lacks visible cleavage, and has specific gravity near 2.6.

Identified September 14, 2026More mineral →

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Physical properties

Hardness about 6.5–7 Mohs; opaque brown, cream, and reddish coloration with earthy to silky luster. It is cryptocrystalline, lacks visible cleavage, and has specific gravity near 2.6.

Formation & geological history

A volcanic silica-rich rock formed when chalcedony and quartz filled cavities or replaced material in ancient volcanic flows, with iron oxides producing the brown-red colors. Classic orbicular material formed in the Miocene of Madagascar, roughly 5–20 million years ago.

Uses & applications

Used for cabochons, beads, carvings, polished display stones, and lapidary collections; it has little structural or industrial use.

Geological facts

The rounded polished form and contrasting rusty matrix are typical of jasper, though distinct orbicular patterns are subtle or absent in this specimen.

Field identification & locations

Identify by its opaque, dense appearance, waxy-to-dull luster, conchoidal fracture, and resistance to scratching by steel; it should not fizz in dilute acid. Common sources include Madagascar, Mexico, India, Brazil, and the western United States.