sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, green, yellow; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58-2.91

Hardness: 6
Color: Reddish-brown, green, yellow
Luster: Vitreous to dull

Identified June 2, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, green, yellow; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58-2.91

Formation & geological history

Formed from silica-rich precipitates in volcanic ash or sedimentary deposits, often during the Proterozoic or Paleozoic eras. Intense pressure and hydrothermal fluids consolidate the microcrystalline quartz.

Uses & applications

Commonly used in lapidary work for jewelry, cabochons, and decorative ornaments. Historically used for making tools and seals.

Geological facts

Jasper is an opaque variety of chalcedony. The red and brown colors are primarily caused by iron inclusions. It has been used as a gemstone since the earliest civilizations.

Field identification & locations

Identify in the field by its waxy luster when broken, conchoidal fracture, and inability to be scratched by a steel knife. Frequently found in riverbeds or coastal beaches as water-worn pebbles.