sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red, Luster: Dull to vitreous, Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal), Cleavage: None/Conchoidal fracture, Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red, Luster: Dull to vitreous, 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 water-rich environments, often in hydrothermal veins or as a secondary replacement mineral in volcanic or sedimentary beds. The red color is caused by high concentrations of iron oxide (hematite).
Uses & applications
Widely used as a gemstone in jewelry (cabochons, beads), decorative carvings, lapidary art, and occasionally as a minor industrial abrasive.
Geological facts
Red Jasper has been used by humans for millennia; it was known as the 'rain-bringer' in ancient cultures and was famously used in the breastplate of the high priest in biblical times.
Field identification & locations
Identify by its deep red color, high hardness (will scratch glass), and smooth, conchoidal (shell-like) fracture pattern. It is commonly found in gravel beds, river banks, and desert environments worldwide, particularly in the US, Brazil, and India.
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