sedimentary

Jasper

Jasper (Silicate mineral, SiO2)

Hardness: 6.5-7 (Mohs); Color: Red, yellow, brown, earthy tones due to iron inclusions; Luster: Dull to vitreous; Crystal Structure: Microcrystalline hexagonal (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, yellow, brown, earthy tones due to iron inclusions
Luster: Dull to vitreous

Identified April 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from mineral-rich fluids in hydrothermal or sedimentary environments. Iron oxides precipitate during formation, providing the distinct coloration. It is primarily found in old Precambrian rocks and volcanic deposits.

Uses & applications

Used frequently in lapidary work for cabochons and beads, as well as an ornamental stone. Historically used for making tools like scrapers due to its conchoidal fracture.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It is mentioned in many ancient texts and has been used for seals and jewelry for thousands of years.

Field identification & locations

Identify in the field by its opacity (it does not transmit light even at the edges), smooth conchoidal fracture, and inability to be scratched by a steel knife. Commonly found in riverbeds or desert pavement.