sedimentary

Jasper

Opaque Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to tan. Luster: Dull to vitreous. Crystal Structure: Trigonal/Microcrystalline. Specific Gravity: 2.58-2.91. Cleavage: None (Conchoidal fracture).

Hardness: 6
Color: Brownish-red to tan
Luster: Dull to vitreous

Identified June 27, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to tan. Luster: Dull to vitreous. Crystal Structure: Trigonal/Microcrystalline. Specific Gravity: 2.58-2.91. Cleavage: None (Conchoidal fracture).

Formation & geological history

Jasper is typically formed in sedimentary environments when silica-rich fluids precipitate into porous rocks or volcanic ash. The brown and red tones are primarily caused by iron oxide (limonite or hematite) impurities within the silica structure.

Uses & applications

Used primarily as a gemstone for jewelry, lapidary cabochons, and decorative ornamental carvings. Historically used for making tools due to its hardness and sharp fracture edges.

Geological facts

The name 'Jasper' originates from the Greek word 'iaspis', meaning spotted stone. It has been used since antiquity for seals and amulets, and was mentioned in the Bible as a stone of the High Priest's breastplate.

Field identification & locations

Identify in the field by its opacity (even on thin edges), its hardness (it will scratch glass), and its smooth, waxy fracture surface. Commonly found in riverbeds and desert environments where volcanic activity once met water.