sedimentary
Banded Agate
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Hardness: 6.5-7 on Mohs scale. Color: Gray, black, and white bands. Luster: Vitreous to waxy. Texture: Smooth, likely water-worn or tumbled. Structure: Cryptocrystalline.
- Hardness
- 6
- Color
- Gray, black, and white bands
- Luster
- Vitreous to waxy
Identified More sedimentary →
Explore Banded 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 Mohs scale. Color: Gray, black, and white bands. Luster: Vitreous to waxy. Texture: Smooth, likely water-worn or tumbled. Structure: Cryptocrystalline.
Formation & geological history
Formed as a secondary deposit in volcanic rock cavities or sedimentary fissures where silica-rich fluids cooled and crystallized over thousands of years in distinctive layers.
Uses & applications
Used primarily in lapidary work for jewelry, decor, and as pocket stones for collectors. Often used for industrial burnishing due to its hardness.
Geological facts
Agate is named after the Achates River in Sicily where it was first discovered by ancient Greeks. Each band represents a different pulse of mineral-saturated fluid flow.
Field identification & locations
Look for distinctive, concentric or parallel banding and a waxy surface texture. This specific specimen’s rounded shape suggests it was weathered by water in a river or lacustrine environment.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Brown Sandstone (River Rock)
Arenite
sedimentary
Mudstone
Argillite / Siliciclastic sedimentary rock
sedimentary
Cone-in-cone structure (Limestone)
Cone-in-cone structure (Secondary Sedimentary Structure)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary