sedimentary
Red Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs); Color: deep brick red; Luster: dull to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: none; Fracture: conchoidal; Specific Gravity: 2.6-2.9.
- Hardness
- 6
- Color
- deep brick red
- Luster
- dull to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs); Color: deep brick red; Luster: dull to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: none; Fracture: conchoidal; Specific Gravity: 2.6-2.9.
Formation & geological history
Formed from the deposition of silica-rich sediments or volcanic ash where iron impurities provide the red color. Typically occurs in hydrothermal veins or as nodules in sedimentary rocks.
Uses & applications
Commonly used for lapidary work, jewelry (cabochons, beads), decorative carvings, and as a popular stone for tumbling and collecting.
Geological facts
The name 'jasper' comes from the Greek word 'iaspis', meaning 'spotted stone'. It is an opaque variety of chalcedony. In ancient times, it was believed to bring rain and provide protection against spirits.
Field identification & locations
Identify by its solid red color, smooth waxy texture when weathered, and high hardness (cannot be scratched by a steel knife). Commonly found in stream beds or on beaches as rounded pebbles.
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