sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Red, brown, and multicolored; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, brown, and multicolored
Luster: Vitreous to waxy

Identified July 7, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Red, brown, and multicolored; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91

Formation & geological history

Formed from the deposition of silica from volcanic ash or hydrothermal circulation in sedimentary environments, often colored by iron oxide inclusions. Specimens range from thousands to billions of years old.

Uses & applications

Used primarily in lapidary work for cabochons, beads, and tumbled stones; also used in decorative ornaments and historical seal stones.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used for jewelry and amulets since ancient Egyptian and Mesopotamian civilizations.

Field identification & locations

Identify by its opacity (unlike translucent agate), high hardness, and earthy patterns. Common in desert environments, riverbeds, and areas with ancient volcanic activity like the western USA, India, and Brazil.