
sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5–7 (Mohs scale), Color: Green and brown bands/mottling, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline (Trigonal), Cleavage: None, Specific Gravity: 2.58–2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5–7 (Mohs scale), Color: Green and brown bands/mottling, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline (Trigonal), Cleavage: None, Specific Gravity: 2.58–2.91
Formation & geological history
Formed through the accumulation of fine silica-rich sediments or volcanic ash that undergoes lithification. This specimen likely formed in an environment with fluctuating mineral content, causing the layered or banded appearance.
Uses & applications
Commonly used for decorative ornaments, lapidary work (tumbling/polishing), jewelry (cabochons), and as a collector's specimen.
Geological facts
Jasper is an opaque variety of chalcedony. The name comes from the Old French 'jaspre', meaning 'spotted or speckled stone'. It has been used as a gemstone since antiquity.
Field identification & locations
Identify in the field by its hardness (will scratch glass), opaque nature, and smooth, conchoidal fracture. Often found as rounded river stones or in desert washes.
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