sedimentary

Polished brecciated jasper

Brecciated jasper, chiefly microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque, salmon-pink, cream, gray, brown, and black angular fragments in a polished vitreous-to-waxy matrix. Massive, cryptocrystalline, with no visible cleavage; specific gravity about 2.5–2.8.

Identified August 23, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when silica-rich sediments or volcanic fragments were broken, cemented, and later silicified, commonly with iron-oxide staining. Individual pieces may range from Paleozoic to Cenozoic, depending on locality.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and decorative objects; rarely used as aggregate or ornamental stone.

Geological facts

The angular, mosaic-like pattern distinguishes brecciated jasper from uniformly banded jasper and many agates. Polishing enhances the contrast between fragments and cement.

Field identification & locations

Identify it by its opaque body, angular clasts, quartz-like hardness, and inability to scratch with a steel knife easily. Brecciated jasper occurs worldwide, notably in the western United States, Mexico, Madagascar, India, and Australia.