mineral

Agate (Chalcedony)

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 Mohs; Color: Varied (yellowish-brown, tan, white banding); Luster: Waxy to vitreous; Crystal Structure: Trigonal (microscopic); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Varied (yellowish-brown, tan, white banding)
Luster: Waxy to vitreous

Identified June 22, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Varied (yellowish-brown, tan, white banding); Luster: Waxy to vitreous; Crystal Structure: Trigonal (microscopic); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed in cavities of volcanic or sedimentary rocks where silica-rich groundwater precipitates over time. This specimen shows typical water-worn or tumbled texture common in riverbed find areas.

Uses & applications

Used extensively in jewelry (cabochons), ornamental carvings, burnishing tools, and as a popular collector's item due to its variety of patterns.

Geological facts

Agate is a variety of chalcedony characterized by its fineness of grain and brightness of color. It was named by Theophrastus, a Greek philosopher, who discovered the stone along the shoreline of the river Achates.

Field identification & locations

Identified by its waxy appearance, translucency, and inability to be scratched by a steel knife. Commonly found in gravel beds, beaches, and areas with volcanic history.