Mineral

Agate (or Quartz with Agate banding)

Silicon dioxide (SiO2)

Hardness of 6.5-7 on Mohs scale. Translucent to semi-opaque, often with white, milky, or clear crystalline areas and distinct black or dark banding on the edge. Vitreous to waxy luster. Cryptocrystalline quartz structure.

Identified June 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich groundwater filling cavities in volcanic rocks over millions of years. Layers are deposited over time, creating bands.

Uses & applications

Commonly polished and shaped into cabochons for jewelry, decorative pieces, and lapidary arts.

Geological facts

Agate a variety of chalcedony. The dark banding seen on the edge is characteristic of onyx or dark agate layers.

Field identification & locations

Identifiable by its hardness (scratches glass), translucency, and often banded appearance. Agates are common worldwide, particularly in volcanic regions.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral