sedimentary

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂) colored by hematite/goethite

AI-generated identification · may be incorrect

Typically Mohs 6.5–7, opaque brick-red to brown, with a dull to waxy luster and conchoidal fracture; quartz has no cleavage and specific gravity around 2.6. The specimen appears dense and freshly fractured, though exact identification requires testing.

Identified September 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich sediment or volcanic material is replaced or cemented, with iron oxides producing the red color; deposits range from Precambrian to younger ages. Common in hydrothermal, sedimentary, and weathering environments.

Uses & applications

Used for cabochons, beads, carvings, lapidary pieces, and occasionally decorative stone; massive material has limited industrial use compared with ordinary chert.

Geological facts

Red coloration generally comes from finely disseminated hematite rather than red quartz crystals. It may grade into chert, radiolarite, or iron-rich quartzite.

Field identification & locations

Look for high hardness, resistance to scratching by steel, opaque red color, and shell-like fracture; it should scratch glass but not be scratched by a steel knife. Common sources include India, Madagascar, Brazil, the United States, and Australia.