sedimentary

Yellow Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5 to 7 on the Mohs scale. Color: Mustard yellow to brownish-yellow. Luster: Dull to vitreous when polished. Crystal Structure: Hexagonal (microcrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.6 to 2.9.

Hardness: 6
Color: Mustard yellow to brownish-yellow
Luster: Dull to vitreous when polished

Identified January 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments. Over time, these fluids solidify into a dense, opaque variety of chalcedony. The yellow hue is primarily due to the presence of goethite or other iron oxides incorporated during formation.

Uses & applications

Commonly used as a gemstone for jewelry, including beads, cabochons, and tumbled stones. It is also utilized for decorative carvings, inlay work, and is highly valued by mineral collectors for its unique patterns and earthy tones.

Geological facts

Jasper has been used by ancient civilizations for centuries to craft seals and ornaments. Yellow Jasper, in particular, was historically known as a stone of protection and discernment. Some varieties are called 'Picture Jasper' if the patterns resemble landscapes.

Field identification & locations

Identify it in the field by its opaque appearance, smooth conchoidal fracture which leaves sharp edges, and its inability to be scratched by a steel knife. It is frequently found in riverbeds and desert regions of the United States, India, and Madagascar.