sedimentary
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
Hardness: 6.5-7 on the Mohs scale; Color: Brownish-tan with lighter vein patterns; Luster: Dull to vitreous/waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brownish-tan with lighter vein patterns
- Luster
- Dull to vitreous/waxy
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Physical properties
Hardness: 6.5-7 on the Mohs scale; Color: Brownish-tan with lighter vein patterns; Luster: Dull to vitreous/waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediment. It often forms in hydrothermal environments or through the replacement of organic materials over millions of years.
Uses & applications
Used in gemstone polishing, lapidary arts, decorative beads, and as an ornamental stone in jewelry. Small river-tumbled pieces like this are common in rock collections.
Geological facts
Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used for seals and amulets since ancient Mesopotamian times.
Field identification & locations
Identify in the field by its opacity (it does not transmit light even at the edges), smooth texture, and conchoidal fracture. Commonly found in riverbeds, beaches, and desert regions globally.
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