mineral
Jasper
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 on Mohs scale; Color: Tan, brown, ochre, or cream mottled; Luster: Dull to waxy when wet; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Tan, brown, ochre, or cream mottled
- Luster
- Dull to waxy when wet
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Tan, brown, ochre, or cream mottled; Luster: Dull to waxy when wet; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.
Formation & geological history
Usually forms from the precipitation of silica from groundwater or hydrothermal fluids in volcanic or sedimentary environments. It is an opaque variety of chalcedony.
Uses & applications
Used primarily for ornamental purposes, jewelry (cabochons, beads), and as a collector's specimen. Its durability makes it suitable for lapidary work.
Geological facts
Jasper is an impure variety of silica, usually containing up to 20% foreign materials which determine its color and opacity. It has been used since ancient times for seals and talismans.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by a steel knife), opaque nature, and smooth, often water-worn rounded surfaces if found in riverbeds. Common in many global locations including the USA, India, and Brazil.
