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: reddish-orange to yellowish-brown; Luster: dull to waxy/sub-vitreous; Fracture: conchoidal to uneven; Specific Gravity: 2.58-2.91

Hardness: 6
Color: reddish-orange to yellowish-brown
Luster: dull to waxy/sub-vitreous

Identified July 26, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: reddish-orange to yellowish-brown; Luster: dull to waxy/sub-vitreous; Fracture: conchoidal to uneven; Specific Gravity: 2.58-2.91

Formation & geological history

Forms primarily through chemical precipitation in microcrystalline quartz beds or by silica replacing organic material or fine silt in low-energy aquatic environments, colored red by micro-inclusions of iron oxides like hematite.

Uses & applications

Commonly used for lapidary work, decorative cabochons, carvings, landscaping, and aggregate.

Geological facts

Red jasper is a microcrystalline variety of quartz that has been used since antiquity for seals, amulets, and ornamental jewelry. Its red coloration is due to fine hematite impurities dispersed throughout the matrix.

Field identification & locations

Can be identified in the field by its high hardness (scratches glass, cannot be scratched by a steel nail), smooth to conchoidal fracture surface, opaque red-orange-brown coloration, and dull to waxy luster. Commonly found along riverbeds, gravel bars, and sedimentary rock formations worldwide.