sedimentary

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Hardness: 6.5-7 (Mohs scale); Color: Yellow to mustard-gold; Luster: Vitreous to waxy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Yellow to mustard-gold
Luster: Vitreous to waxy

Identified March 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water or volcanic ash. The yellow color is typically provided by goethite or other iron hydroxide minerals during the sedimentary process. It is found in deposits ranging from Precambrian to more recent geological ages.

Uses & applications

Commonly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and in alternative medicine practices. Historically used for tool making due to its conchoidal fracture which creates sharp edges.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' is derived from the Greek 'iaspis', meaning 'spotted stone'. In ancient times, it was considered a powerful protective stone and was often used in the breastplates of high priests.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate) and its smooth, waxy surface when polished or water-worn. Found frequently in riverbeds and coastal regions globally, notably in India, Russia, Brazil, and the USA (California and Oregon).

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