sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown and greenish-grey, Luster: Dull to waxy, Crystal Structure: Microcrystalline trigonal, Cleavage: None/Conchoidal fracture.

Hardness: 6

Identified July 16, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown and greenish-grey, Luster: Dull to waxy, Crystal Structure: Microcrystalline trigonal, Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed from tiny silica-rich materials that settled in deep oceans or near volcanic activity. Over millions of years, heat and pressure consolidated these into a dense, opaque microcrystalline quartz.

Uses & applications

Commonly used in jewelry (cabochons, beads), decorative carvings, and as a popular lapidary material for hobbyists.

Geological facts

Jasper is an opaque variety of chalcedony. The red color is typically caused by iron (hematite) inclusions, while the green can result from silicate minerals or iron oxidation states.

Field identification & locations

Identify in the field by its opacity (even on thin edges), its characteristic conchoidal fracture (curved breaks), and its ability to scratch glass. Found globally in areas with ancient silica-rich deposits.