mineral

Agate Geode

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5-7 on Mohs scale; Color: White, translucent, and iron-stained orange/brown; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64.

Hardness: 6
Color: White, translucent, and iron-stained orange/brown
Luster: Waxy to vitreous

Identified April 13, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities within volcanic or sedimentary rocks. Silica-rich groundwater percolates through these voids, depositing layers of chalcedony over thousands of years to create the banded agate and inner crystalline druse.

Uses & applications

Used primarily for lapidary work, jewelry, interior decoration, and as a collector's specimen due to its aesthetic banding and hollow center.

Geological facts

Agates are some of the oldest healing stones in history. This specific specimen features a 'druzy' center where tiny quartz crystals have formed within the hollow cavity.

Field identification & locations

Identify in the field by looking for rounded nodules with a rough, weathered exterior but a translucent, banded interior when broken. Commonly found in riverbeds or volcanic ash deposits in regions like Brazil, Mexico, or the Western USA.

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