sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2 plus various impurities)

Hardness: 6.5-7 (Mohs); Color: Red, orange, or reddish-brown due to iron inclusions; Luster: Dull to greasy; Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, orange, or reddish-brown due to iron inclusions
Luster: Dull to greasy

Identified May 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich water into volcanic ash or fine-grained sediment. The red coloring usually suggests the presence of iron oxides (hematite) during formation. It can be found across various geological ages, often in ancient volcanic or sedimentary provinces.

Uses & applications

Commonly used in lapidary work for making cabochons, beads, and stone ornaments. Also used for gemstone therapy, garden landscaping (in larger forms), and as a collector's specimen.

Geological facts

Jasper has been used for thousands of years as jewelry and talismans; it was a favorite gem in ancient Mesopotamia and Egypt. It is technically an opaque variety of chalcedony.

Field identification & locations

Identify by its waxy-to-dull luster, opacity (even at thin edges), and inability to be scratched by a steel knife. Frequently found in stream beds or beach gravel as rounded pebbles. Common in the USA, Brazil, India, and Australia.

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