sedimentary
Red Jasper (Mahogany Obsidian variant similarity)
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs); Color: Reddish-brown to brick red; Luster: Vitreous to dull (waxy when polished); Crystal Structure: Microcrystalline trigonal; Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Reddish-brown to brick red
- Luster
- Vitreous to dull (waxy when polished)
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Reddish-brown to brick red; Luster: Vitreous to dull (waxy when polished); Crystal Structure: Microcrystalline trigonal; Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica in hydrothermal veins or sedimentary environments, often colored by iron oxide (hematite) during chemical precipitation. It can be found in various geological ages from Precambrian to recent.
Uses & applications
Primarily used for decorative purposes, jewelry (cabochons, beads), metaphysical practices, and as a durable material for small carvings or tumbled stones.
Geological facts
Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used as a gemstone since antiquity and was a favorite in the ancient world for seals.
Field identification & locations
Identify by its opacity (even when held to light), its characteristic reddish-brown hue, and smooth, conchoidal fracture. It is common in regions with volcanic or sedimentary activity such as India, Brazil, and the USA.
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