mineral

Banded Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Hardness: 6.5-7 (Mohs scale); Color: Gray, black, and brown banding; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.

Hardness: 6
Color: Gray, black, and brown banding
Luster: Vitreous to waxy

Identified April 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities of volcanic rocks or ancient lavas, where silica-rich groundwater deposited layers of microcrystalline quartz over time, often resulting in rhythmic banding.

Uses & applications

Used primarily in lapidary arts for jewelry (cabochons, beads), decorative ornaments, and as a healing stone in metaphysical communities. Historically used for making precision bearings and mortar and pestle sets.

Geological facts

The name Agate comes from the Achates River in Sicily, where agates were first discovered by the Greek philosopher Theophrastus around the 4th century BC. Each stone's banding pattern is unique like a fingerprint.

Field identification & locations

Identify in the field by its distinct translucent or opaque banding, lack of cleavage, and extreme hardness (will scratch glass). Commonly found in riverbeds, shorelines, and areas with ancient volcanic activity.

Other mineral specimens

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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