Jasper (Yellow Jasper)

Physical Properties

Hardness: 6.5–7 on Mohs scale; Color: Mustard yellow to golden brown; Luster: Dull to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.91

Formation & Geological History

Formed from silica-rich fluids that seep through porous sedimentary rock or volcanic ash, replacing minerals over millions of years. Often associated with thermal spring activity or prehistoric ocean floors.

Uses & Applications

Primarily used for lapidary work, jewelry (cabochons), as an ornamental stone, and in metaphysical rock collecting.

Geological Facts

Jasper is an opaque variety of chalcedony. Yellow jasper specifically gets its coloring from the presence of geothite or iron oxyhydroxide within the quartz structure.

Field Identification & Locations

Identify by its opacity (it will not let light pass through like agate) and its smooth, waxy feel when tumbled. Common in desert regions of India, Russia, and the Western USA.

Identified on: 4/14/2026

Mode: Standard