Rock Identifier
Polished orbicular jasper (likely ocean jasper) (Microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂) — mineral
mineral

Polished orbicular jasper (likely ocean jasper)

Microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; rounded brown, cream, and gray patterning with a waxy to glassy luster. It is cryptocrystalline, lacks visible cleavage, and commonly has specific gravity near 2.6.

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Physical properties

Hardness about 6.5–7 Mohs; rounded brown, cream, and gray patterning with a waxy to glassy luster. It is cryptocrystalline, lacks visible cleavage, and commonly has specific gravity near 2.6.

Formation & geological history

Forms when silica-rich fluids replace or cement volcanic material, while iron oxides and other inclusions create orbicular or brecciated patterns. Ocean jasper is chiefly associated with Oligocene–Miocene volcanic rocks of Madagascar, though similar orbicular jaspers occur worldwide.

Uses & applications

Used for cabochons, beads, carvings, polished spheres, and lapidary collectibles; it has little industrial value.

Geological facts

The image shows a small polished sphere with concentric, brecciated-looking inclusions; exact identification is limited without an unpolished surface or locality information.

Field identification & locations

Identify it by its opaque patterned body, glassy/waxy polish, lack of cleavage, and resistance to scratching by steel; glass or dyed agate can look similar. Common sources include Madagascar, Mexico, Oregon, and Australia.