sedimentary
Banded Agate (with possible Chalcedony layers)
Silicon dioxide (SiO2)
Hardness: 6.5-7 on Mohs scale. Color: Multicolored bands including blue, tan, and reddish-brown. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/cryptocrystalline quartz). Cleavage: None. Specific gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Multicolored bands including blue, tan, and reddish-brown
- Luster
- Waxy to vitreous
Identified More sedimentary →
Explore Banded Agate (with possible Chalcedony layers) 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: Multicolored bands including blue, tan, and reddish-brown. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/cryptocrystalline quartz). Cleavage: None. Specific gravity: 2.58-2.64.
Formation & geological history
Formed primarily in volcanic and metamorphic rocks as a secondary mineral through the deposition of silica from groundwater into cavities (vesicles) or cracks. The banding is caused by rhythmic crystallization cycles over thousands of years.
Uses & applications
Used extensively in jewelry as gemstones (cabochons), ornamental carvings, bookends, and industrial mortars and pestles due to its hardness and resistance to chemicals.
Geological facts
Agate was named by Theophrastus, a Greek philosopher, who discovered the stone along the shore line of the river Achates in modern-day Sicily. It is one of the oldest healing stones in history.
Field identification & locations
Identify by its characteristic colorful banding and waxy translucency. Common in the Lake Superior region (USA), Brazil, and Germany. Collectors look for sharp, high-contrast bands and unique color patterns.
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
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary