sedimentary

Jasper

Silicon Dioxide (SiO2) with impurities

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish; Luster: Waxy to dull; Crystal structure: Microcrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Brown, tan, reddish
Luster: Waxy to dull

Identified July 4, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Brown, tan, reddish; Luster: Waxy to dull; Crystal structure: Microcrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Formation & geological history

Formed through the accumulation of fine-grained silica-rich sediments or volcanic ash that undergo lithification and silification. Often found in riverbeds or coastal areas where it has been smoothed by water erosion.

Uses & applications

Used primarily in jewelry as cabochons, for ornamental carving, and by collectors. Historically used for making tools due to its hardness and sharp fracture edges.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek word 'iaspis', meaning spotted stone. It is often found in riverbeds where it exhibits a natural water-worn polish.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), waxy luster when wet, and lack of transparency. Commonly found in river gravels, beaches, and sedimentary basins worldwide.