mineral

Yellow Agate

Agate (Microcrystalline Silicon Dioxide, SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Translucent yellow with milky white concentric banding; Luster: Vitreous to waxy; Structure: Cryptocrystalline trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Translucent yellow with milky white concentric banding
Luster: Vitreous to waxy

Identified March 9, 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 into cavities (vugs) within volcanic lavas or metamorphic rocks. The distinct yellow hue is often caused by trace amounts of iron oxides or inclusions. Common across many geological ages from the Precambrian to Cenozoic.

Uses & applications

Predominantly used for ornamental purposes, including jewelry (pendants, beads), decorative carvings, and as 'healing' crystals in holistic communities. Historically used in precise balances and mortars due to its hardness.

Geological facts

Agate is named after the Achates River in Sicily where it was first discovered. The circular patterns visible on this specimen are characteristic of the 'eye' or 'banding' effect that occurs as silica-rich fluids cool and solidify in layers.

Field identification & locations

Identify in the field by its waxy appearance, translucency, and inability to be scratched by a steel knife. It is commonly found in riverbeds, shorelines, or areas with former volcanic activity. Popular locations include Brazil, India, and the Midwestern USA.

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