Rock Identifier
Orbicular jasper (likely ocean jasper) (Silica-rich microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂) — mineral
mineral

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque cream, tan, and gray with dark branching or orbicular patterns; vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded shape indicates natural water-worn material or tumbling.

Identified More mineral
Explore Orbicular jasper (likely ocean jasper) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

Hardness about 6.5–7 Mohs; opaque cream, tan, and gray with dark branching or orbicular patterns; vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded shape indicates natural water-worn material or tumbling.

Formation & geological history

Forms when silica-rich volcanic fluids or ash lithify and later develop iron- and manganese-rich inclusions, brecciation, or orbicular textures. Classic ocean jasper formed in volcanic rocks of Madagascar, chiefly Mesozoic to Cenozoic in age.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and lapidary display; not generally used as structural stone. Value depends on pattern, polish, color, and provenance.

Geological facts

The image most strongly suggests orbicular or scenic jasper, though exact identification requires a close examination of texture and a hardness or specific-gravity test. Jasper is an opaque variety of chalcedony rather than a single mineral species.

Field identification & locations

Look for opaque silica, smooth conchoidal fracture, waxy/vitreous luster, and resistance to scratching by steel; calcite or limestone would be much softer. Common sources include Madagascar, Oregon, Idaho, Mexico, Brazil, and India.