sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Opaque reddish-brown and tan with earthy tones. Luster: Dull to waxy. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None, conchoidal fracture.

Hardness: 6
Color: Opaque reddish-brown and tan with earthy tones
Luster: Dull to waxy

Identified May 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water-rich environments like seabed sediment or groundwater in volcanic ash. This process of silicification occurs over millions of years, often colored by iron oxides.

Uses & applications

Commonly used as a gemstone for jewelry, lapidary carvings, and ornamental stones. Historically used for making tools due to its hardness and sharp fracture edges.

Geological facts

Jasper has been used by civilizations for millennia; it was mentioned in many ancient texts and used for cylinder seals in Mesopotamia. The name comes from the Greek word 'iaspis', meaning spotted stone.

Field identification & locations

Identify in the field by its opacity (even when held to light), its smoothness when water-worn, and its ability to scratch glass. Found globally in riverbeds, beaches, and desert regions.