Because of its vast array of minerals, Idaho lives up to its original nickname as the Gem State, according to the Idaho Department of Lands. Congress designated the Idaho Territory in 1863, naming it after the Shoshone word for "gem." Today, rockhounds find many gems in Idaho, including rubies, pink garnets, amethyst, opal, fire opals, star garnets, agates and sapphires.
Opal is an iridescent stone whose color changes when observed from different angles. It is found in a number of areas in Idaho, including in southeastern Idaho at the Spencer Opal Mine. Opened in 1948, the mine is less than a one-hour drive north of Idaho Falls. Spencer Opal Mine is no longer in operation as a commercial mine, but you can still visit it. Pay a small fee to try your hand at digging for opals and keep what you find.
The star garnet is Idaho’s state gem. It is a silicate related to quartz and is called a star garnet because some samples display a reflection like a four- or six- pointed star. Gem-quality garnets are mined commercially in the Little North Fork and North Fork areas. You can try sluicing for star garnets yourself at the Emerald Creek Garnet Area in the Idaho Panhandle National Forest near Clarkia, Idaho. The Forest Service stockpiles gravel that may contain garnets and provides two sluice boxes. You need to buy a permit and can keep up to 5 lbs. of garnets with your daily permit.
Agates come in many colors. They look iridescent when cut into slabs. Popular spots to look for agates include Succor Creek, Mann Creek, Beacon Hill and Bennett Mountain, according to the Idaho Department of Lands. Check the Idaho Department of Land’s website for its rockhound code of ethics and information on rockhounding on state endowment lands and public land. Tips include respecting private property, leaving no garbage behind, filling in excavations and leaving gates as they were found.
Jasper is an opaque quartz that can be red, yellow, brown or dark green in color. Jasper is found in the Paris Canyon near Montpelier, along Little Wood River, in Beacon Hill near Weiser and in Bruneau River Canyon south of Bruneau. The Bruneau jaspers are red and green gem-quality stones, according to the Idaho Museum of History's Digital Atlas of Idaho.