mineral
Tumbled banded blue agate
Chalcedony (microcrystalline quartz, SiO₂), variety agate
AI-generated identification · may be incorrectPolished, rounded specimen with blue and pale gray-white bands. Quartz hardness is 6.5–7 Mohs; vitreous to waxy luster and cryptocrystalline structure, with no visible cleavage. Blue coloring may be natural or enhanced; the photo cannot establish this.
Identified More mineral →
Explore Tumbled banded blue agate in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Polished, rounded specimen with blue and pale gray-white bands. Quartz hardness is 6.5–7 Mohs; vitreous to waxy luster and cryptocrystalline structure, with no visible cleavage. Blue coloring may be natural or enhanced; the photo cannot establish this.
Formation & geological history
Agate forms as silica-rich fluids fill cavities, commonly in volcanic rocks, and deposit successive chalcedony bands. The specimen’s age and locality cannot be determined from the image.
Uses & applications
Used for jewelry, ornaments, and collecting; agate is also used for carvings and small decorative objects.
Geological facts
Agate is a banded form of chalcedony; tumbling smooths the surface but does not identify its source or whether its color was treated.
Field identification & locations
Look for curved or concentric bands and a glassy-to-waxy polish; hardness and banding help distinguish it from dyed glass. Agates occur worldwide, including Brazil, Uruguay, India, and the United States.
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