sedimentary
Red Jasper
Silicon dioxide (microcrystalline quartz with iron oxide inclusions), SiO2
Hardness: 6.5-7 (Mohs scale); Color: Brick red to deep terracotta; Luster: Dull to vitreous; Crystal structure: Hexagonal (trigonal) microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red to deep terracotta
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to deep terracotta; Luster: Dull to vitreous; Crystal structure: Hexagonal (trigonal) microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica-rich waters in hydrothermal veins or sedimentary environments. Its red color comes from high concentrations of iron oxide (hematite) inclusions that saturated the quartz during formation.
Uses & applications
Used widely in lapidary work for cabochons, beads, and carvings. Historically used for seals and amulets. Today it is popular among crystal collectors and as a semi-precious gemstone in jewelry.
Geological facts
In ancient times, Red Jasper was known as the 'stone of endurance' and was often carried by warriors for protection and courage. It is an opaque variety of chalcedony that can be polished to a extremely high gloss.
Field identification & locations
Identify in the field by its deep red color, characteristic conchoidal fracture (curved, glass-like breaks), and high hardness—it will scratch steel but cannot be scratched by a knife. Commonly found in areas with high iron content and silica deposits like South Africa, Brazil, and the USA (California and Oregon).
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