sedimentary

Yellow Chalcedony or River Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Yellow-brown, honey-colored, translucent to opaque; Luster: Waxy or dull; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.64

Hardness: 6
Color: Yellow-brown, honey-colored, translucent to opaque
Luster: Waxy or dull

Identified April 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica-rich fluids at low temperatures in cavities or as nodules within sedimentary rocks. Its smooth, rounded shape indicates it was polished by water over a long period in a river or coastal environment.

Uses & applications

Used primarily for lapidary work, cabochons, and ornamental carvings. It is popular among mineral collectors and can be used in tumbled stone jewelry.

Geological facts

Jasper and chalcedony are both microcrystalline varieties of quartz; jasper is typically differentiated by its opacity and high impurity content. This specimen has the classic 'river-worn' texture from mechanical weathering.

Field identification & locations

Identify in the field by its waxy luster, smoothness, and the fact that it cannot be scratched by a steel knife. Common in riverbeds, especially in areas with ancient volcanic or sedimentary activity.

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