sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale). Color: Earthy red, brown, yellow. Luster: Dull to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None, conchoidal fracture. Specific gravity: 2.58-2.91.

Hardness: 6
Color: Earthy red, brown, yellow
Luster: Dull to vitreous

Identified May 3, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale). Color: Earthy red, brown, yellow. Luster: Dull to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None, conchoidal fracture. Specific gravity: 2.58-2.91.

Formation & geological history

Formed through the accumulation of fine siliceous material from volcanic ash or micro-plankton (radiolitids) in sedimentary environments. Its appearance is often a result of iron impurities mineralizing over millions of years.

Uses & applications

Commonly used as a gemstone for jewelry (cabochons), interior decoration, ornamental carvings, and historical use as striking stones for flintlock weapons.

Geological facts

Jasper has been used by humans since antiquity; the name is derived from the Greek word 'iaspis', meaning spotted stone. It was a favorite gemstone in the ancient world, mentioned in both Greek and Biblical literature.

Field identification & locations

Identify by its opacity (even on thin edges), smooth conchoidal fracture, and inability to be scratched by a steel knife. Frequently found in riverbeds and desert environments.