sedimentary

Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Dark grey/brown with subtle banding, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline/cryptocrystalline (Trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified June 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed primarily from the deposition of silica from water in sedimentary environments or volcanic ash. The grey color is often due to organic impurities or iron inclusions. Most specimens are millions of years old, originating from the Paleozoic to Cenozoic eras.

Uses & applications

Tumbled stones are used for decoration, lapidary arts, metaphysical practices, and as inexpensive collecting specimens. High-quality Jasper is used in jewelry and ornaments.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek 'iaspis', meaning 'spotted stone.' It has been used by ancient civilizations for seals and talismans for over 7,000 years.

Field identification & locations

Identify in the field by its opacity (even when held to light), conchoidal (shell-like) fracture, and inability to be scratched by a steel knife. Commonly found in riverbeds or beaches where rocks have been naturally tumbled.