sedimentary

Yellow Jasper

Silicon Dioxide (SiO2) with goethite or limonite inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Mustard yellow to brownish-yellow; Luster: Dull or waxy to vitreous; Crystal Structure: Hexagonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.91

Hardness: 6
Color: Mustard yellow to brownish-yellow
Luster: Dull or waxy to vitreous

Identified June 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich fluids permeate through volcanic ash or sedimentary beds, precipitating microcrystalline quartz and trapping iron oxides during the silicification process.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons, beads), decorative carvings, and as a collector's specimen. Historically used for making tools and weapons due to its conchoidal fracture.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek word 'iaspis', meaning 'spotted stone.' Yellow jasper was traditionally used as a protective stone by shamans and ancient travelers.

Field identification & locations

Identify by its yellow-brown color, opacity (light will not pass through even thin edges), and conchoidal (shell-like) fracture patterns. Frequently found in riverbeds or desert regions globally, especially in Oregon (USA), South Africa, and Madagascar.