sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Brown, red, and tan with mottled patterns, Luster: Vitreous to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified June 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water into volcanic ash or sedimentary beds, often through hydrothermal activity or groundwater circulation. Jasper is typically found in Precambrian to Cenozoic formations.

Uses & applications

Widely used as a gemstone for jewelry, decorative ornaments, lapidary art, and historical use in making tools or seals due to its toughness.

Geological facts

The word 'Jasper' is derived from the Greek 'iaspis', meaning spotted stone. It is an opaque variety of chalcedony and has been a favorite gemstone since the ancient world, often mentioned in various religious texts and mythologies.

Field identification & locations

Identify in the field by its opacity, hardness (won't scratch with a knife), and smooth, waxy surface when polished. Commonly found in river beds and desert environments globally.