sedimentary

Polished Orbicular Jasper tower

Orbicular jasper (microcrystalline quartz/chalcedony with iron oxides and accessory minerals)

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque tan, brown, gray, and black orbicular pattern; vitreous to waxy luster; cryptocrystalline quartz with no visible cleavage; specific gravity roughly 2.55–2.70.

Identified August 24, 2026More sedimentary →

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Physical properties

Hardness about 6.5–7 Mohs; opaque tan, brown, gray, and black orbicular pattern; vitreous to waxy luster; cryptocrystalline quartz with no visible cleavage; specific gravity roughly 2.55–2.70.

Formation & geological history

Formed when silica-rich fluids cemented volcanic or sedimentary material and produced concentric mineral growths; individual deposits are generally Cenozoic or older, depending on locality. This specimen has been cut and polished into a faceted point.

Uses & applications

Used for cabochons, carvings, decorative towers, and collector specimens; not generally used as a structural stone. Typical value is aesthetic rather than gem rarity.

Geological facts

The circular markings are orbicules, commonly created by rhythmic replacement or precipitation around nuclei. Similar material is marketed under locality names such as ocean jasper, although not every orbicular jasper is Ocean Jasper.

Field identification & locations

Identify by its opaque, patterned chalcedony-like body, low translucency, and inability to scratch with a steel knife; quartz should scratch glass. Common sources include Madagascar, Mexico, Australia, and the western United States.