sedimentary
Banded Agate (Tumbled)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Translucent grey with blue/grey banding; Luster: Vitreous to waxy; Structure: Cryptocrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Translucent grey with blue/grey banding
- Luster
- Vitreous to waxy
Identified More sedimentary →
Explore Banded Agate (Tumbled) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Translucent grey with blue/grey banding; Luster: Vitreous to waxy; Structure: Cryptocrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64.
Formation & geological history
Formed in cavities of volcanic or sedimentary rocks through the deposition of silica-rich groundwater. Associated with silica precipitation over thousands to millions of years.
Uses & applications
Jewelry, lapidary art, spiritual healing practices, industrial burnishing tools, and as a popular collector's item for beginners.
Geological facts
Agate is a variety of chalcedony. The name comes from the Achates River in Sicily where it was first discovered in ancient times. Banding is caused by rhythmic crystallization cycles.
Field identification & locations
Look for translucent surfaces with distinct internal or external concentric bands. It is commonly found in riverbeds and on beaches worldwide, particularly in Brazil and the Great Lakes region.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Cone-in-cone structure (Limestone)
Cone-in-cone structure (Secondary Sedimentary Structure)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary