mineral

Yellow Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Translucent yellow to honey-orange; Luster: Waxy to vitreous; Crystal structure: Cryptocrystalline (Trigonal/Monoclinic); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

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

Identified March 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous and sedimentary rocks. This specific rounded shape indicates secondary weathering or river/beach tumbling over thousands of years.

Uses & applications

Commonly used in jewelry as cabochons, decorative carvings, metaphysical stones, and as tumble-polished collector specimens.

Geological facts

Yellow chalcedony is often referred to as 'yellow agate' when it shows banding, though this specimen appears more uniform. It has been used since antiquity for seals and amulets because it does not stick to hot wax.

Field identification & locations

Identify in the field by its waxy surface, translucent edges when held to light, and lack of visible grains. Common in riverbeds, volcanic ash beds, and coastal gravels worldwide (e.g., Brazil, India, USA).

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