sedimentary
Red Jasper
Silicon Dioxide (SiO2) - variety of Chalcedony
Hardness: 6.5–7 on Mohs scale; Color: Terracotta red to brownish-red; Luster: Vitreous to dull; Crystal structure: Hexagonal (trigonal microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.91
- Hardness
- 6
- Color
- Terracotta red to brownish-red
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Terracotta red to brownish-red; Luster: Vitreous to dull; Crystal structure: Hexagonal (trigonal microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.91
Formation & geological history
Formed through the deposition of silica from volcanic ash or hydrothermal solutions into cracks and cavities within sedimentary and igneous environments. It is an opaque variety of chalcedony that owes its red color to iron inclusions (hematite). Specimens can date back to the Proterozoic or Paleozoic eras.
Uses & applications
Primarily used for lapidary work including jewelry, cabochons, beads, and polished palm stones. Also utilized for decorative carvings and as a historical gemstone for amulets and seals.
Geological facts
In ancient times, Red Jasper was known as the 'bringer of courage' and was often used in Egyptian amulets shaped like the 'Knot of Isis.' It is considered a stone of endurance and stability in various metaphysical traditions.
Field identification & locations
Identify in the field by its deep red color, opacity (it does not transmit light even on thin edges), and smooth, shell-like (conchoidal) fracture pattern. Commonly found in South Africa, Brazil, India, and the southwestern United States.
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