mineral
Polished banded agate
Agate, microcrystalline quartz (SiO₂; chiefly chalcedony)
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; glossy polish, translucent-to-opaque gray and cream bands, with a rounded natural-looking inclusion. Quartz has a trigonal crystal structure, though agate’s microscopic crystals are not individually visible; specific gravity about 2.6.
Identified More mineral →
Explore Polished 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 Mohs; glossy polish, translucent-to-opaque gray and cream bands, with a rounded natural-looking inclusion. Quartz has a trigonal crystal structure, though agate’s microscopic crystals are not individually visible; specific gravity about 2.6.
Formation & geological history
Silica-rich groundwater deposited successive chalcedony layers in a cavity, likely in volcanic rock. Agates form across many geological ages; the specimen has been cut and polished.
Uses & applications
Used for jewelry, ornaments, and collecting; agate is also used for small decorative and precision objects.
Geological facts
Agate banding records changing conditions as silica precipitated, and some bands can reveal concentric or fortification patterns.
Field identification & locations
Look for waxy luster, translucency at thin edges, and curved or parallel bands; common sources include Brazil, Uruguay, India, and the United States. The pictured polished piece is too small and lacks detail for a precise variety identification.
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
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
igneous