mineral

Polished orbicular jasper (likely ocean jasper)

Microcrystalline quartz (SiO₂), chiefly chalcedony with iron oxides and other silicate inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque pale green, cream, and brown banding with a waxy to vitreous polish. Usually massive and non-cleavable, with conchoidal fracture; specific gravity roughly 2.5–2.7.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or fill cavities in volcanic rock, incorporating iron and other mineral impurities; the attractive orbicular/banded textures developed during alteration. Ocean jasper is chiefly associated with Cenozoic volcanic rocks of Madagascar.

Uses & applications

Used for cabochons, carvings, polished slabs, beads, and decorative objects; modestly valued as a lapidary material.

Geological facts

“Jasper” is a broad trade and geological term for opaque, impurity-rich chalcedony or microcrystalline quartz. The specimen appears cut and polished rather than naturally weathered.

Field identification & locations

Identify by its opaque silica body, hardness, waxy polish, and irregular green-cream-brown bands or orbicules; it should resist scratching by steel. Common sources include Madagascar, India, Brazil, and the western United States.