gemstone
Agate
Silicon Dioxide (Chalcedony variety), SiO2
Hardness: 6.5-7 on the Mohs scale, Color: Various including gray, white, blue, yellow, red, and brown, Luster: Waxy to vitreous, Crystal structure: Trigonal (microcrystalline quartz)
- Hardness
- 6
Identified More gemstone →
Explore Agate in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 on the Mohs scale, Color: Various including gray, white, blue, yellow, red, and brown, Luster: Waxy to vitreous, Crystal structure: Trigonal (microcrystalline quartz)
Formation & geological history
Formed by the deposition of silica from groundwater in the cavities of igneous or sedimentary rocks, often over millions of years.
Uses & applications
Used in jewelry, ornamentation, making mortars and pestles, and as a collector's specimen.
Geological facts
Agates are known for their distinct concentric banding patterns which form as different impurities enter the silica solution during deposition.
Field identification & locations
Can be identified in the field by its waxy luster, conchoidal fracture, and characteristic banding. Commonly found in riverbeds, volcanic regions, and pebble beaches worldwide.
More like this
Other gemstone specimens
Diamond and Gold Jewelry
Carbon (Diamond) / Au (Gold)
gemstone
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Cubic Zirconia (simulant) or Diamond
ZrO2 (Cubic Zirconia) or C (Diamond)
gemstone
Black Opal Ring (Carved Opal)
Hydrated Silicon Dioxide (SiO2·nH2O)
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Cubic Zirconia (or possibly Diamond)
Zirconium dioxide (or Carbon)
gemstone