Jasper

Silicon dioxide (SiO2) with iron oxide impurities

Rock Type: sedimentary

Jasper

Physical Properties

Hardness: 6.5–7 (Mohs scale); Color: Reddish-brown/orange; Luster: Dull to waxy; Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58–2.91

Formation & Geological History

Formed from the precipitation of silica in sedimentary environments, often associated with iron-rich deposits that provide the red/orange coloration. They frequently undergo further smoothing and shaping through fluvial (river) or glacial transport.

Uses & Applications

Commonly used as a semi-precious gemstone in jewelry, for decorative items like cabochons and beads, and in lapidary work as it takes a high polish.

Geological Facts

Jasper has been used by ancient civilizations for thousands of years; the name is derived from the Greek 'iaspis', meaning 'spotted stone.' This specific specimen appears to be a river-worn pebble.

Field Identification & Locations

Identify in the field by its smooth, matte texture when dry and its inability to be scratched by a steel knife. It is commonly found in riverbeds, beaches, and gravel pits globally.

Identified on: 4/13/2026

Mode: Standard