mineral
Agate (Chalcedony)
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 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 More mineral →
Explore Agate (Chalcedony) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
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.
