sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Red, brown, earthy tones; Luster: Dull to Vitreous; Crystal System: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91

Hardness: 6
Color: Red, brown, earthy tones
Luster: Dull to Vitreous

Identified May 9, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Red, brown, earthy tones; Luster: Dull to Vitreous; Crystal System: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91

Formation & geological history

Formed through the silicification of volcanic ash or fine-grained sediments in hydrothermal or sedimentary environments. It is often found in prehistoric deposits ranging from millions to billions of years old.

Uses & applications

Commonly used for lapidary work, jewelry (beads, cabochons), decorative stones, and historical use in tool-making (scrapers/arrowheads).

Geological facts

Jasper is an opaque variety of chalcedony. The red color seen in this specimen is typically caused by iron inclusions. It has been used by humans for over 7,000 years, including by ancient Egyptians for amulets.

Field identification & locations

Identify in the field by its opacity, conchoidal fracture, and inability to be scratched by a steel knife. Frequently found in riverbeds, glacial tills, and desert pavements.