sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7.0 (Mohs scale); Color: Yellow-brown, mustard, ochre; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.

Hardness: 6
Color: Yellow-brown, mustard, ochre
Luster: Vitreous to waxy

Identified June 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water or hydrothermal fluids, often in volcanic or sedimentary environments. Most specimens range from several million to hundreds of millions of years old.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and decorative carvings. It is popular in jewelry and for collecting as a semi-precious gemstone.

Geological facts

Jasper is an opaque variety of chalcedony. The yellow coloring is typically caused by the presence of iron inclusions (limonite or goethite). It has been used for seals and amulets since ancient times.

Field identification & locations

Identify in the field by its opaque nature (it does not transmit light unlike agate), conchoidal (shell-like) fracture, and smooth, waxy feel. It is commonly found in gravel beds, riverbanks, and volcanic regions worldwide.