mineral

Fairburn Agate

Cryptocrystalline Quartz (SiO2) with trace Iron Oxides

Hardness: 6.5-7 (Mohs), Color: red, white, orange, and gray bands, Luster: Waxy to vitreous, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)

Hardness: 6

Identified June 21, 2026More mineral →

Explore Fairburn Agate in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6.5-7 (Mohs), Color: red, white, orange, and gray bands, Luster: Waxy to vitreous, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)

Formation & geological history

Formed during the Mississippian Period about 330 million years ago within limestone cavities. They are sedimentary-hosted agates often found in river beds and gravel deposits after eroding from their host rock.

Uses & applications

Used primarily as a gemstone for jewelry, lapidary art, and as a highly sought-after collector's item due to unique fortification patterns.

Geological facts

The Fairburn Agate is the official state gemstone of South Dakota. It is named after the town of Fairburn, SD, where it was first discovered in the Black Hills.

Field identification & locations

Identified by sharp, angular 'fortification' bands and vibrant color contrasts. Found in the Buffalo Gap National Grasslands and southern Black Hills. Collectors look for 'holly leaf' or star-shaped banding patterns.

Other mineral specimens

See all

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