sedimentary
Red Jasper (possibly Agatized Jasper)
Jasper (Silicon Dioxide, SiO2 with Fe2O3 inclusions)
Hardness: 6.5–7 on the Mohs scale. Color: Deep red to brownish-red with white quartz/agate veins. Luster: Dull to waxy (can be vitreous when polished). Crystal structure: Microcrystalline/Cryptocrystalline trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.91.
- Hardness
- 6
- Color
- Deep red to brownish-red with white quartz/agate veins
- Luster
- Dull to waxy (can be vitreous when polished)
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Physical properties
Hardness: 6.5–7 on the Mohs scale. Color: Deep red to brownish-red with white quartz/agate veins. Luster: Dull to waxy (can be vitreous when polished). Crystal structure: Microcrystalline/Cryptocrystalline trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.91.
Formation & geological history
Formed through the deposition of silica from hydrothermal solutions or within sedimentary environments. The red color is caused by high concentrations of iron oxide (hematite) inclusions. It can form in various geological ages, often found in ancient volcanic or sedimentary beds.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons and beads), ornamental carvings, and as a popular specimen for crystal collecting and home decor.
Geological facts
Jasper has been used by humans for thousands of years; it was a favorite gem in the ancient world, mentioned in biblical texts and used by the Minoans to create seals. When it contains translucent bands, it is often referred to as 'Jasp-agate'.
Field identification & locations
Identify in the field by its opaque nature, smooth waxy texture, and conchoidal (shell-like) fracture patterns. It will scratch glass but cannot be scratched by a steel knife. Commonly found in riverbeds, deserts, and gravel pits in areas like the Western USA (e.g., Oregon and Idaho), India, and Brazil.
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