mineral

Banded Agate (with Quartz Geode Center)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: White, gray, dark brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (cryptocrystalline); Specific gravity: 2.6

Hardness: 6
Color: White, gray, dark brown
Luster: Vitreous to waxy

Identified June 27, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: White, gray, dark brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (cryptocrystalline); Specific gravity: 2.6

Formation & geological history

Formed as secondary minerals in cavities of volcanic rock (vesicles) through the deposition of silica-rich groundwater. Over time, layers of chalcedony build up, often leaving a hollow or quartz-filled center.

Uses & applications

Commonly used in lapidary work, jewelry (cabochons), interior decoration, and as metaphysical or collector specimens.

Geological facts

The bands in agate are formed by the rhythmic crystallization of silica. No two agates are exactly alike, making each one unique to its specific chemical environment during formation.

Field identification & locations

Identify by its characteristic banding and translucent nature when held to light. Often found in riverbeds, gravel pits, and areas with ancient volcanic activity.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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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