Rock Identifier
Polished orbicular jasper (likely ocean jasper or brecciated jasper) (Microcrystalline quartz (SiO₂), with iron oxides and accessory chlorite/zeolite minerals) — mineral
mineral

Polished orbicular jasper (likely ocean jasper or brecciated jasper)

Microcrystalline quartz (SiO₂), with iron oxides and accessory chlorite/zeolite minerals

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque, multicolored brown, gold, gray, green, and black with a waxy to vitreous polish. Massive cryptocrystalline quartz lacks cleavage; density is typically 2.5–2.7 g/cm³.

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Physical properties

Hardness about 6.5–7 Mohs; opaque, multicolored brown, gold, gray, green, and black with a waxy to vitreous polish. Massive cryptocrystalline quartz lacks cleavage; density is typically 2.5–2.7 g/cm³.

Formation & geological history

Formed when silica-rich volcanic fluids filled cavities or cemented volcanic fragments, with iron oxidation producing the yellow-brown colors. Most jasper is Paleozoic to Mesozoic or younger, depending on locality.

Uses & applications

Used for cabochons, carvings, worry stones, bookends, and lapidary collectibles; rarely used as construction stone.

Geological facts

The visible pattern reflects brecciation, flow banding, and mineral staining rather than large crystals. “Ocean jasper” is a trade name, not a single officially defined mineral species.

Field identification & locations

Identify it by its opaque, fine-grained texture, curved fracture, strong polish, and lack of visible quartz crystals; a steel file should barely scratch it. Common sources include Madagascar, Oregon, California, Mexico, and Australia.