sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Opaque reddish-brown due to iron inclusions. Luster: Vitreous to dull. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.58-2.91.

Hardness: 6
Color: Opaque reddish-brown due to iron inclusions
Luster: Vitreous to dull

Identified May 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water-rich environments, often near volcanic activity or in sedimentary basins. The red color is typically caused by iron oxide (Hematite) impurities. Most jasper dates from various geological periods, often thousands to millions of years old.

Uses & applications

Used primarily for ornamental purposes, jewelry (cabochons, beads), decorative carvings, and as a popular collector's stone. Historically used for making tools due to its hardness and sharp fracture edges.

Geological facts

Jasper is a densly packed variety of microcrystalline quartz. In ancient times, 'Red Jasper' was known as the 'Stone of Endurance' and was frequently used by warriors for protection and strength. It is distinct from agate because it is opaque rather than translucent.

Field identification & locations

Identify by its opacity, smooth waxy surface when polished, and conchoidal fracture. Red jasper often exhibits a 'brick-like' or 'dried blood' color with occasional quartz veins. Commonly found in the USA (Oregon, California, Idaho), Brazil, and India.