sedimentary
Jasper
Silicon dioxide (SiO2) with impurities
Hardness: 6.5-7 (Mohs scale), Color: Brown/Opaque, Luster: Vitreous to waxy, Crystal structure: Trigonal/Microcrystalline, 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: Brown/Opaque, Luster: Vitreous to waxy, Crystal structure: Trigonal/Microcrystalline, Cleavage: None/Conchoidal fracture, Specific gravity: 2.58-2.91
Formation & geological history
Formed through the accumulation of fine-grained silica in sedimentary environments or by replacement of volcanic ash with silica during hydrothermal activity.
Uses & applications
Used in ornamental jewelry, lapidary art, decorative carvings, and as a semi-precious gemstone.
Geological facts
Jasper is an impure variety of silica. The name comes from the Greek 'iaspis', meaning 'spotted stone.' It is a member of the chalcedony family.
Field identification & locations
Identify in the field by its hardness (scratches glass), opaque nature, and smooth, conchoidal fracture. Often found in riverbeds or as beach pebbles like the one shown.
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