sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Multi-colored with red, yellow, and grey-blue; Luster: Waxy to vitreous; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Multi-colored with red, yellow, and grey-blue
Luster: Waxy to vitreous

Identified July 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Jasper is an opaque variety of chalcedony formed through the deposition of silica from water-rich environments, often occurring in volcanic or sedimentary rocks as nodules or vein fillings. The colors are caused by mineral impurities like iron oxides.

Uses & applications

Used primarily in lapidary arts for decorative stones, jewelry (cabochons), beading, and as a popular specimen for rock tumbling and collection.

Geological facts

Jasper has been used as a gemstone since antiquity and was a favorite in the ancient world, frequently mentioned in biblical texts and used for seals and amulets. The name is derived from the Greek word 'iaspis', meaning spotted stone.

Field identification & locations

Identify by its opacity (it does not transmit light even at the edges), smooth waxy feel when polished, and high hardness. It is common in riverbeds and on beaches in volcanic regions.