sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron impurities
Hardness: 6.5-7.0 (Mohs scale); Color: Red, earthy brown; Luster: Dull to vitreous; Crystal Structure: Hexagonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Red, earthy brown
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7.0 (Mohs scale); Color: Red, earthy brown; Luster: Dull to vitreous; Crystal Structure: Hexagonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91
Formation & geological history
Forms through the deposition of silica in groundwater or hydrothermal fluids within volcanic ash or sedimentary beds. The red color is caused by the inclusion of fine-grained hematite during formation.
Uses & applications
Used in jewelry (beads, cabochons), ornamental carvings, and as a powerful grounding stone in lapidary collecting.
Geological facts
Red Jasper has been used since ancient times for amulets and seals. It is a variety of chalcedony that is opaque due to its high mineral content (often up to 20% iron).
Field identification & locations
Identify in the field by its deep red color, smooth waxy feel when polished, and sharp, shell-like edges when broken. Commonly found in riverbeds and desert environments globally.
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