mineral

Yellow Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Hardness: 6.5-7 (Mohs scale); Color: Pale yellow to honey-gold; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (microscopic); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.

Hardness: 6
Color: Pale yellow to honey-gold
Luster: Waxy to vitreous

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich groundwater in cavities of igneous rocks or sedimentary layers. This specific specimen appears to be water-worn and tumbled, likely deposited during the Neogene or Quaternary periods along riverbeds or coastlines.

Uses & applications

Commonly used in lapidary work for cabochons and beads, as healing stones in metaphysical practices, and as ornamental garden stones. High-quality translucent pieces are used for minor jewelry.

Geological facts

Yellow chalcedony is often called 'Gold Agate' by enthusiasts. Unlike crystalline quartz (like Citrine), its structure is composed of sub-microscopic fibers, giving it a characteristic translucency rather than transparency.

Field identification & locations

Identify in the field by its smooth, 'soapy' texture, lack of visible crystals, and its ability to scratch glass. It is commonly found in gravel pits, riverbeds, and beaches across the Pacific Northwest and volcanic regions of Brazil and Uruguay.

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