mineral

Yellow Chalcedony

Silicon Dioxide (SiO2)

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

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

Identified April 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed at low temperatures as a precipitate from silica-rich groundwater in cavities of various rock types, including volcanic gas bubbles and sedimentary cracks. Can date from various geological ages.

Uses & applications

Primarily used in jewelry as cabochons, for ornamental sculptures, and as a popular specimen for crystal collectors due to its warm color and smooth texture.

Geological facts

The word Chalcedony is believed to be derived from the name of the ancient Greek town Chalcedon in Asia Minor. It is a microcrystalline variety of quartz.

Field identification & locations

Identify by its waxy luster, lack of visible crystals, and hardness (it can scratch glass). Commonly found in Brazil, India, Madagascar, and the USA. Collectors look for uniform color and high translucency.