sedimentary

Brecciated jasper or brecciated chert

Silica-rich breccia, chiefly microcrystalline quartz (SiO₂), with iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, cream, reddish, and gray angular fragments in a lighter silica matrix; typically dull to waxy luster, opaque, and lacks visible cleavage. Fractures are generally conchoidal; specific gravity is roughly 2.5–2.7.

Identified August 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when preexisting chert or jasper fragments were broken, transported or tectonically fractured, then cemented by silica-rich fluids; iron oxides produce the red-brown colors. It may range from Paleozoic to Cenozoic depending on its locality.

Uses & applications

Used as lapidary material for cabochons, carvings, polished specimens, and ornamental stone; rarely used as aggregate or minor decorative building stone.

Geological facts

The angular clasts distinguish breccia from conglomerate, whose clasts are rounded. Its appearance can resemble brecciated jasper, chert, or quartz vein material.

Field identification & locations

Look for glassy or waxy silica texture, sharp fragment boundaries, conchoidal breaks, and the ability to scratch ordinary glass. Common in hydrothermal veins, fault zones, volcanic terrains, and sedimentary chert beds; exact identification would benefit from a locality and streak or hardness test.