sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Vitreous to waxy (when polished), dull (unpolished); Crystal structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red to brownish-red
- Luster
- Vitreous to waxy (when polished), dull (unpolished)
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Vitreous to waxy (when polished), dull (unpolished); Crystal structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica-rich fluids in sedimentary or hydrothermal environments. Its red color is derived from high concentrations of hematite (iron oxide) diffused throughout the mineral. It can be found across various geological ages, often in Banded Iron Formations.
Uses & applications
Primarily used for decorative purposes, lapidary arts, jewelry (cabochons and beads), and as a collector's stone. Historically used for seals and carvings.
Geological facts
Jasper was a favorite gem in the ancient world; its name can be traced back to Greek, Hebrew, and Persian roots meaning 'spotted or speckled stone.' It is often found in large deposits rather than individual crystals.
Field identification & locations
Identify in the field by its opaque nature (it does not transmit light even on thin edges), its characteristic conchoidal fracture, and its inability to be scratched by a steel knife. Commonly found in South Africa, Brazil, India, and the southwestern USA.
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