sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on the Mohs scale. Color: Reddish-brown, opaque. Luster: Vitreous to dull. Crystal structure: Hexagonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58–2.91.

Hardness: 6
Color: Reddish-brown, opaque
Luster: Vitreous to dull

Identified April 13, 2026More sedimentary →

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Physical properties

Hardness: 6.5–7 on the Mohs scale. Color: Reddish-brown, opaque. Luster: Vitreous to dull. Crystal structure: Hexagonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58–2.91.

Formation & geological history

Usually formed from silica-rich fluids in volcanic regions or in sedimentary beds where microscopic silica particles (like radiolarian ooze) solidify. This specimen appears water-worn, likely tumbled in a river or beach setting.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), ornamental carvings, and as a popular collector's stone due to its ability to take a high polish.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone.' It has been used since antiquity for seals and amulets.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of transparency even on thin edges (unlike agate), and smooth, often waxy or water-worn surface when found in stream beds.