sedimentary
Red Jasper
Chalcedony with Iron Oxide (SiO2 with Fe2O3)
Hardness: 6.5-7 Mohs; Color: Brick red to deep terracotta; Luster: Vitreous to waxy (when polished); Crystal Structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red to deep terracotta
- Luster
- Vitreous to waxy (when polished)
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Physical properties
Hardness: 6.5-7 Mohs; Color: Brick red to deep terracotta; Luster: Vitreous to waxy (when polished); Crystal Structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.91
Formation & geological history
Formed via the deposition of silica from hydrothermal solutions or during the diagenesis of sedimentary layers where volcanic ash or fine sediments are present. The red color is caused by the inclusion of high concentrations of iron oxide (hematite).
Uses & applications
Widely used for lapidary work including tumbled stones, cabochons for jewelry, decorative carvings, and as a healing stone in metaphysical practices. Historically used for making tools and seals.
Geological facts
Red Jasper has been used since antiquity; it was known in Ancient Egypt for amulets and in the Bible as one of the stones in the breastplate of the High Priest. It is often referred to as the 'Supreme Nurturer' in gemstone folklore.
Field identification & locations
Identify by its deep red color, opacity (light does not pass through), and smooth soapy feel when polished. It cannot be scratched by a steel knife. Commonly found in Brazil, India, USA, and South Africa.
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