Rock Identifier
Yellow Jasper (Silicon Dioxide (SiO2) with iron hydroxides (goethite)) — sedimentary
sedimentary

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides (goethite)

Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Dull to greasy, Crystal structure: Microcrystalline/Cryptocrystalline (Trigonal), Opaque with some conchoidal fracture.

Hardness
6
Identified More sedimentary
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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Dull to greasy, Crystal structure: Microcrystalline/Cryptocrystalline (Trigonal), Opaque with some conchoidal fracture.

Formation & geological history

Formed through the accumulation of fine silica-rich sediment or volcanic ash, which becomes mineralized over millions of years. The yellow color is derived from iron impurities (goethite/limonite).

Uses & applications

Used in lapidary work for cabochons, beads, and sculpture. Historically used for ornaments and tools due to its hardness and ability to hold an edge.

Geological facts

Jasper has been a popular gemstone since antiquity, mentioned in many historical texts. Yellow jasper is specifically associated with travelers and perceived as a stone of protection.

Field identification & locations

Identify in the field by its opaque nature, hardness (cannot be scratched by a steel knife), and smooth, waxy surface when broken. Found globally in riverbeds and desert environments.