sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5–7 on the Mohs scale; Color: Green, olive, and brownish; Luster: Vitreous to waxy; Crystal structure: Microcrystalline/Trigonal (Cryptocrystalline quartz); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.91.

Hardness: 6
Color: Green, olive, and brownish
Luster: Vitreous to waxy

Identified May 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine-grained silica in sedimentary or volcanic environments. The green coloration is typically due to the inclusion of iron silicate minerals or chlorite. This process occurs over millions of years as silica-rich fluids permeate through rock cavities or volcanic ash.

Uses & applications

Commonly used in jewelry as cabochons, beads, and ornamental carvings. It is also used in lapidary art and as a collector's stone due to its smoothness and variety of patterns.

Geological facts

Jasper has been used as a gemstone since antiquity and is mentioned in various historical texts. The name translates from Old French, Latin, and Greek to mean 'spotted or speckled stone.'

Field identification & locations

Identified in the field by its opacity, hardness (it can scratch glass but not quartz), and its smooth, river-worn or tumbled texture. Found globally, with notable deposits in India, Russia, Brazil, and the USA (Pacific Northwest).