sedimentary
Jasper (Red Chert)
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Deep red to reddish-brown with grayish veins; Luster: Dull to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Deep red to reddish-brown with grayish veins
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Deep red to reddish-brown with grayish veins; Luster: Dull to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
Formation & geological history
Formed from the deposition of microcrystalline quartz or silica-rich volcanic ash. This specific rounded specimen underwent significant water-erosion (river or beach rounding) over thousands of years.
Uses & applications
Commonly used in lapidary work for cabochons, beads, and decorative ornaments. Often used as a pocket stone or for landscaping due to its durability.
Geological facts
Jasper has been used by humans for thousands of years; it was a favorite gem in antiquity, mentioned in many ancient texts for its supposed protective virtues.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by a steel knife) and its smooth, waxy feel when polished by water. Commonly found in riverbeds and along coastlines globally.
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