sedimentary

Jasper (Red/Yellow)

Silicon Dioxide (SiO2) with impurities

Hardness: 6.5-7 (Mohs scale); Color: Red and brownish-yellow; Luster: Dull to waxy; Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red and brownish-yellow
Luster: Dull to waxy

Identified April 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Jasper forms when fine silicate materials or volcanic ash are deposited in sedimentary environments and then silicified. The red color comes from iron (hematite) inclusions, while the yellow comes from goethite or limonite. Many specimens found in riverbeds or beaches are from the Paleozoic or Mesozoic eras.

Uses & applications

Commonly used for lapidary work, decorative cabochons for jewelry, small carvings, and as a popular specimen for rock tumbling and collecting.

Geological facts

Jasper is an opaque variety of chalcedony. Throughout history, it has been known as a 'nurturing stone' and was used in ancient Egypt and Mesopotamia for seals and amulets.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate) and its hardness—it will scratch glass and cannot be scratched by a steel knife. Commonly found in river gravels, desert washes, and coastal beaches.

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