sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red; Luster: Dull to vitreous/waxy; Crystal Structure: Hexagonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Brick red to brownish red
- Luster
- Dull to vitreous/waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red; Luster: Dull to vitreous/waxy; Crystal Structure: Hexagonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.
Formation & geological history
Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments. Over time, the silica crystallizes into microcrystalline quartz. The deep red color is caused by the presence of hematite (iron oxide) impurities. It can be found in formations ranging from the Archean to the Cenozoic eras.
Uses & applications
Used widely in lapidary work for cabochons, beads, and carvings. In industry, it is sometimes used as an ornamental building stone or for precision bearings. It is a popular 'healing stone' in metaphysical communities and a common beginner collector's specimen.
Geological facts
Jasper was a favorite gem in antiquity and is mentioned in many historical texts, including the Bible. The name comes from the Greek word 'iaspis', meaning 'spotted stone.' It is an opaque variety of chalcedony.
Field identification & locations
Identify in the field by its deep red color, total opacity (even when held to light), and characteristic shell-like (conchoidal) fracture pattern. It cannot be scratched by a steel knife. Common locations include India, Brazil, Madagascar, and the western United States (California, Oregon).
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