sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown with variegated patterns, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline quartz, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown with variegated patterns, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline quartz, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica from water-saturated solutions, often associated with volcanic ash or sedimentary environments. The brown-red coloring typically comes from iron oxide inclusions.
Uses & applications
Used primarily for lapidary arts, jewelry (cabochons), interior decoration, and as a popular collector's stone due to its polishing capabilities.
Geological facts
Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It was highly valued in the ancient world for its supposed healing properties.
Field identification & locations
Identify in the field by its hardness (it can scratch glass) and opaque nature with a smooth, almost soapy feel when wet. It is commonly found in riverbeds, beaches, and desert plains globally.
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