sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 Mohs; Color: Red, yellow, brown, or green; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91

Hardness: 6
Color: Red, yellow, brown, or green
Luster: Vitreous to dull

Identified June 18, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Red, yellow, brown, or green; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91

Formation & geological history

Formed from silica-rich fluids in volcanic ash or sedimentary deposits, often during the Proterozoic or Paleozoic eras. It forms as a result of chemical precipitation from mineral-rich water.

Uses & applications

Commonly used for lapidary work, jewelry (beads, cabochons), ornamental seals, and as a decorative stone in home decor.

Geological facts

The name comes from the Greek word 'iaspis', meaning spotted stone. Historically, it was believed to provide protection and was worn as amulets by various ancient civilizations.

Field identification & locations

Identify by its opacity (even when held to light), waxy to dull luster, and high hardness. It is frequently found in riverbeds or coastal areas where it has been tumbled smooth.