mineral
Polished agate slice
Agate, a banded variety of chalcedony (microcrystalline SiO₂)
AI-generated identification · may be incorrectMohs hardness 6.5–7; translucent white-gray chalcedony with purple and tan bands, vitreous to waxy luster, and no visible cleavage. The specimen is cut and polished; its exact variety cannot be determined from the image alone.
Identified More mineral →
Explore Polished agate slice in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness 6.5–7; translucent white-gray chalcedony with purple and tan bands, vitreous to waxy luster, and no visible cleavage. The specimen is cut and polished; its exact variety cannot be determined from the image alone.
Formation & geological history
Agate forms as silica-rich fluids fill cavities, commonly in volcanic rocks, depositing successive layers. The age varies with its host rock and cannot be determined from appearance.
Uses & applications
Used for jewelry, ornaments, and lapidary crafts; this thin polished slice is primarily decorative or collectible.
Geological facts
Agate’s colors and bands reflect differences in mineral impurities and deposition conditions; some commercial agates are dyed.
Field identification & locations
Look for translucent chalcedony and curved or irregular bands; common sources include Brazil, Uruguay, India, and the United States. Estimated value: about $5–$25 for a small polished slice, depending on size and workmanship.
More like this
Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous