sedimentary
Jasper
Silicon dioxide (SiO2) with iron oxide impurities
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
- Hardness
- 6
- Color
- Reddish-brown/orange
- Luster
- Dull to waxy
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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.
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