sedimentary

Red Jasper (Chert)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5–7 on Mohs scale; Color: Deep brick red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91.

Hardness: 6
Color: Deep brick red to brownish-red
Luster: Dull to vitreous

Identified March 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich fluids in volcanic or sedimentary environments, often associated with Banded Iron Formations (BIFs). The red color is derived from high concentrations of oxidized iron (hematite) during the lithification process.

Uses & applications

Extensively used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as an ornamental stone in landscaping and interior design. Historically used for making tools and seals.

Geological facts

Jasper has been revered since antiquity; in the ancient world, it was known as the 'supreme nurturer.' It is a variety of chalcedony that is opaque due to the mineral impurities that give it its distinctive color patterns.

Field identification & locations

Identify in the field by its characteristic waxy to dull luster, lack of cleavage, and extreme hardness (it will scratch glass). Common locations include the Lake Superior region (USA), South Africa, India, and Brazil. Collectors should look for smooth, water-worn cobbles in riverbeds.