sedimentary
Jasper with Iron Staining
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
Hardness: 6.5-7 (Mohs scale); Color: Opaque reddish-brown to creamy-white mottled with rust; Luster: Waxy to earthy; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); SG: 2.58-2.91
- Hardness
- 6
- Color
- Opaque reddish-brown to creamy-white mottled with rust
- Luster
- Waxy to earthy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Opaque reddish-brown to creamy-white mottled with rust; Luster: Waxy to earthy; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); SG: 2.58-2.91
Formation & geological history
Formed through the infiltration of silica in hydrothermal veins or sedimentary beds, with the red-orange coloring coming from high concentrations of iron oxide (Rust/Hematite). Often found in ancient volcanic or sedimentary sequences.
Uses & applications
Used primarily for lapidary work, cabochons, and garden decoration. Historically used for making tools due to its conchoidal fracture.
Geological facts
Jasper was a favorite gem in antiquity; it is mentioned in the Bible and was frequently used in ancient seals and jewelry in Mesopotamia and Egypt.
Field identification & locations
Identify in the field by its opaque nature (unlike translucent agate) and its hardness—it will scratch glass but cannot be scratched by a steel knife. Common in desert pavements and river beds.
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