sedimentary

Brecciated jasper/chert

Microcrystalline quartz (SiO₂), with iron-oxide and clay inclusions

AI-generated identification · may be incorrect

Typically opaque, mottled cream, red, brown, and gray, with a dull to waxy luster and conchoidal fracture; Mohs hardness about 6.5–7, no cleavage, and specific gravity around 2.5–2.7. The specimen appears brecciated or strongly weathered, though the image alone cannot distinguish jasper from closely related chert.

Identified August 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or cements sediment, volcanic material, or fractured rock; red coloration commonly comes from hematite. Such material ranges from Precambrian to recent, depending on its host deposit.

Uses & applications

Used as ornamental stone, cabochons, beads, carvings, and polished display pieces; generally unsuitable for structural construction because of its irregularity.

Geological facts

Jasper is a variety of opaque chalcedony/microcrystalline quartz, and brecciation produces its patchy, angular color patterns.

Field identification & locations

Test for hardness by scratching glass, inspect for a waxy luster and conchoidal fracture, and check that red zones are embedded rather than surface coating. Common in silica-rich volcanic and sedimentary terrains worldwide, including the western United States, Madagascar, Brazil, and Australia.