sedimentary

Pink Chert (Brecciated Jasmine/Jasper)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Pink, reddish-brown, and white/grey; Luster: Waxy to vitreous; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6 – 2.7.

Hardness: 7 on Mohs scale
Color: Pink, reddish-brown, and white/grey
Luster: Waxy to vitreous

Identified March 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains (like radiolaria) or chemical precipitation in marine environments. The brecciated (fragmented) appearance suggests later tectonic fracturing followed by silica infilling, often during the Paleozoic or Mesozoic eras.

Uses & applications

Used primarily in lapidary work for cabochons and decorative carvings. Historically used by indigenous peoples for stone tools (scrapers, arrowheads) due to its sharp conchoidal edges.

Geological facts

Chert is so durable that it often survives billions of years of erosion. This specific pinkish-red hue is usually caused by trace amounts of iron oxide (hematite) within the silica matrix.

Field identification & locations

Identify in the field by its waxy texture, smooth curved (conchoidal) fractures, and its ability to scratch glass. Commonly found in limestone or chalk beds as nodules or massive layers in regions like Lake Superior, the Ozarks, and various riverbeds.

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