mineral

Yellow Chalcedony (Agate)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Translucent yellow to honey-amber. Luster: Waxy to vitreous. Crystal Structure: Trigonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.6-2.64.

Hardness: 6
Color: Translucent yellow to honey-amber
Luster: Waxy to vitreous

Identified July 9, 2026More mineral →

Explore Yellow Chalcedony (Agate) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous rocks or sedimentary layers. It develops slowly over millions of years at relatively low temperatures.

Uses & applications

Used primarily in jewelry (cabochons and beads), decorative carvings, and as a healing stone in holistic practices. Also collected as river-tumbled specimens.

Geological facts

Yellow chalcedony is often called 'the speaker's stone' in folklore. Its coloration usually comes from trace amounts of iron oxides (limonite) trapped within the microscopic quartz fibers.

Field identification & locations

Look for a waxy surface, translucency when held to the light, and a lack of visible crystal grains. They are commonly found in riverbeds, gravel pits, and coastal areas where volcanic activity once occurred.