mineral

Banded Agate (with Quartz Geode Center)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Gray, white, and translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal (Trigonal); Cleavage: None; SG: 2.58–2.64.

Hardness: 6
Color: Gray, white, and translucent
Luster: Vitreous to waxy

Identified May 1, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Gray, white, and translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal (Trigonal); Cleavage: None; SG: 2.58–2.64.

Formation & geological history

Formed in volcanic rock cavities or ancient sedimentary rocks. Silica-rich groundwater deposits layers of chalcedony over time, often ending with macro-crystalline quartz centers. Most date back to the Cretaceous or Tertiary periods.

Uses & applications

Primarily used for lapidary arts, jewelry, carvings, and as decorative metaphysical specimens or paperweights.

Geological facts

The distinctive banding is caused by rhythmic crystallization cycles. This specific specimen is a 'polished point' or 'tower' which has been cut and polished to highlight the interior banding.

Field identification & locations

Identify in the field by its waxy luster and concentric banding when broken or cut. Common in Brazil, Uruguay, and the Lake Superior region of the USA.

Other mineral specimens

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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