mineral

Banded Agate (specifically Chalcedony nodule)

Agate (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on Mohs scale. Color: Translucent orange, pink, and white bands. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Translucent orange, pink, and white bands
Luster: Waxy to vitreous

Identified March 12, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks such as basalt. Over millions of years, varying mineral impurities (like iron and manganese) create the distinct colorful banding.

Uses & applications

Predominantly used for lapidary work (cabochons), jewelry, ornamental carvings, and as a collector's specimen. Historically used for making mortars and pestles and hard-wearing burnishing tools.

Geological facts

Agate nodules often form inside volcanic gas bubbles called vesicles. This specimen shows 'water-level' or horizontal banding, indicating it remained stationary while the silica-rich fluids filled the cavity. Many agates are millions of years old, dating back to the Cenozoic or Mesozoic eras.

Field identification & locations

Identify in the field by its waxy luster, translucency when held to light, and distinctive concentric or horizontal color bands. Commonly found in riverbeds, shorelines, or areas with eroded volcanic soil such as the Great Lakes region or the American Southwest.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral