sedimentary

Iron-rich chert/jasper

Chalcedony (microcrystalline quartz, SiO₂) with iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; reddish-brown to yellow-brown, mostly dull to waxy or subtly glassy luster, opaque to translucent edges, and conchoidal fracture with no cleavage. The yellow-brown crust likely contains limonite/goethite and weathered matrix.

Identified August 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably formed when silica-rich fluids replaced or cemented sediment, with later iron-oxide weathering producing the red and ochre colors. Exact age cannot be determined from the photograph; such material occurs in many Paleozoic to younger sedimentary terrains.

Uses & applications

Used as decorative stone, lapidary rough, cabochons, beads, and occasionally as a flaking material for prehistoric tools. Common pieces generally have modest commercial value.

Geological facts

The specimen’s curved fracture and waxy surface are characteristic of chert or jasper rather than a crystalline quartz vein. Its strong coloration comes mainly from dispersed iron oxides, not necessarily from hematite crystals.

Field identification & locations

Look for very fine grain, conchoidal fracture, hardness sufficient to scratch ordinary glass, and a lack of visible individual crystals. Common in sedimentary outcrops, gravel deposits, and weathered iron-rich zones; locality information or testing is needed for a precise identification.