sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Deep reddish-brown to brick red; Luster: Dull to vitreous; Crystal structure: Hexagonal (microcrystalline/cryptocrystalline); Specific gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Deep reddish-brown to brick red
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Deep reddish-brown to brick red; Luster: Dull to vitreous; Crystal structure: Hexagonal (microcrystalline/cryptocrystalline); Specific gravity: 2.58-2.91.
Formation & geological history
Formed through the infiltration of silica-rich fluids into volcanic or sedimentary deposits. The red color is caused by the high iron content (hematite inclusions) incorporated during the silicification process.
Uses & applications
Predominantly used for lapidary work, jewelry (beads, cabochons), ornamental décor, and as a pocket stone for collectors and enthusiasts.
Geological facts
Red jasper was known in antiquity as the 'stone of endurance' and was often used for seals and talismans in ancient Egypt and Rome. It is a variety of chalcedony.
Field identification & locations
Identify by its opaque red color and high hardness (it cannot be scratched by a steel knife). Look for it in riverbeds or gravel deposits near volcanic regions. Commonly found in South Africa, Brazil, and the USA.
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