mineral

Agate (specifically a Banded Agate with a Quartz Druzy center)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Banded white, tan, and gray with crystalline quartz. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Banded white, tan, and gray with crystalline quartz
Luster: Vitreous to waxy

Identified June 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic host rock (igneous) where cavities or vesicles were filled by silica-rich groundwater. Over time, rhythmic deposition of silica layers created the bands, often leaving a hollow or crystal-filled center (druzy).

Uses & applications

Used primarily in lapidary arts, jewelry, gemstone collecting, and historically for making burnishing tools or mortars and pestles due to its hardness.

Geological facts

Agate is a variety of chalcedony. The name comes from the Achates River in Sicily where they were first found. Every agate is unique due to the specific mineral impurities present during its formation.

Field identification & locations

Identify in the field by looking for translucent banded patterns and a waxy luster when wet. Often found in riverbeds, glacial till, or volcanic outcrops. Common in Lake Superior region, Brazil, and India.

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