sedimentary

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions

Hardness: 6.5-7 (Mohs); Color: Deep brick red to brownish-red; Luster: Vitreous to dull (waxy when polished); Crystal Structure: Microcrystalline/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Deep brick red to brownish-red
Luster: Vitreous to dull (waxy when polished)

Identified March 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich fluids in volcanic ash or sedimentary rocks, often associated with hydrothermal activity. Its red color is derived from iron (hematite) impurities integrated during the silicification process.

Uses & applications

Extensively used in lapidary work for making cabochons, beads, and ornamental carvings. Historically used for seals and weapon handles; currently used in construction as decorative stone in mosaics.

Geological facts

Ancient Egyptians associated red jasper with the blood of Isis and used it for amulets. It is an opaque variety of chalcedony that breaks with a smooth, curved fracture surface.

Field identification & locations

Identify in the field by its opacity (it does not transmit light even on thin edges), its characteristic deep red color, and it will scratch glass but cannot be scratched by a steel knife. Common in diverse locations including Brazil, India, USA (Southwest), and South Africa.

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