sedimentary
Jasper
Microcrystalline Quartz (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, red to reddish-brown color due to iron oxide impurities, dull to greasy luster, cryptocrystalline or microcrystalline structure, conchoidal fracture with no true cleavage, and a specific gravity of 2.58 to 2.91.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, red to reddish-brown color due to iron oxide impurities, dull to greasy luster, cryptocrystalline or microcrystalline structure, conchoidal fracture with no true cleavage, and a specific gravity of 2.58 to 2.91.
Formation & geological history
Formed through the precipitation of silica-rich fluids in sedimentary environments or hydrothermal veins, often replacing existing carbonate rocks or volcanic ash over millions of years.
Uses & applications
Used in ornamental carvings, jewelry, lapidary art, and as a decorative stone.
Geological facts
Jasper has been used since ancient times to create seals, talismans, and decorative items. Its rich red varieties are often referred to as red jasper.
Field identification & locations
Can be identified in the field by its hardness (scratches glass), waxy to dull luster, and opaque red coloration. Commonly found in riverbeds, alluvial gravels, and ancient sedimentary formations worldwide.
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