sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick-red to brownish-red; Luster: Vitreous to dull; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58–2.91
- Hardness
- 6
- Color
- Brick-red to brownish-red
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick-red to brownish-red; Luster: Vitreous to dull; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58–2.91
Formation & geological history
Formed through the deposition of silica from volcanic ash or hydrothermal solutions into cracks and voids. Its red color originates from iron oxide (hematite) inclusions that occur during sedimentation or diagenesis.
Uses & applications
Primarily used for lapidary work, cabochons for jewelry, decorative carvings, and as a popular pocket stone for crystal collectors.
Geological facts
In antiquity, jasper was considered the 'mother of all stones' by many cultures. It is an opaque variety of chalcedony that breaks with a smooth, conchoidal fracture which prehistoric humans used to make tools.
Field identification & locations
Identify in the field by its intense red color, opacity (it will not let light through even at thin edges), and its ability to scratch glass. Commonly found in India, Brazil, Madagascar, and the Southwestern United States.
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