sedimentary
Jasper
Microcrystalline Quartz (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, brown to reddish-brown color, vitreous to dull luster, cryptocrystalline or microcrystalline crystal structure, conchoidal fracture, specific gravity of 2.58 to 2.91.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, brown to reddish-brown color, vitreous to dull luster, cryptocrystalline or microcrystalline crystal structure, conchoidal fracture, specific gravity of 2.58 to 2.91.
Formation & geological history
Formed through the silification of sedimentary or volcanic rocks, where silica-rich fluids precipitate microcrystalline quartz in pore spaces or fractures. Geological age varies widely depending on the deposit, often ranging from Precambrian to Cenozoic.
Uses & applications
Used in ornamental objects, jewelry, cabochons, carvings, and as a collector specimen.
Geological facts
Jasper has been used since ancient times for talismans, seals, and jewelry. Brown jasper often features interesting banding or web-like patterns called spiderweb jasper.
Field identification & locations
Can be identified by its opaque nature, conchoidal fracture, high hardness (scratches glass), and distinct earthy or multicolored patterns. Found worldwide in riverbeds, desert regions, and mountainous areas.
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