mineral

Polished brecciated jasper or iron-rich chert

Microcrystalline quartz (SiO₂) with hematite/goethite and iron-oxide matrix

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque tan, brown, gray, and rust-red with a waxy to dull luster and irregular brecciated pattern. Quartz is cryptocrystalline, so individual crystals and cleavage are not visible; high density is typical.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich material is deposited or replaces host rock, then fractures and is recemented by iron-bearing fluids. Precise age cannot be determined visually; jasper and chert occur from Precambrian to recent geological settings.

Uses & applications

Used as an ornamental and lapidary stone for tumbled specimens, cabochons, carvings, and small decorative objects; not generally used as a major construction stone.

Geological facts

The reddish-brown colors are caused mainly by hematite and goethite. Its smooth rounded surface indicates tumbling or natural water abrasion, and the specimen may be marketed as brecciated jasper, picture jasper, or iron jasper.

Field identification & locations

Identify by its opaque appearance, very fine texture, conchoidal fracture, and inability to scratch it with a steel knife; quartz should scratch glass. Common sources include Brazil, India, Madagascar, Australia, and the western United States.