Idaho is called the "Gem State" for good reason. Every corner of the state has gems and minerals that can be found. The Star Garnet is the state gemstone, and a wide variety of other beautiful minerals including opals, jasper, quartz, amethyst, petrified wood, and so much more can be found in the beautiful state of Idaho.
Amethyst in Idaho
There are many locations in Idaho where quartz crystals can be found. Crystals come in many varieties, most often clear. However some locations produce smoky quartz, rose quartz, and the highly desirable amethyst crystals.
Amethyst has been found at Pole Creek in Blaine County, Hog Creek in Washington County west of Weiser, along the North Fork of the Lost River, on the Yankee Fork near Stanley, and Challis Creek in near Custer. In Butte County, amethyst has been found at Antelope Creek and Road Creek. Amethyst has also been found on War Eagle Mountain in Owyhee County near the famous mining town of Silver City.
Sapphire
There are a few places known to have found sapphire in Idaho. Rhodes Creek and Orofine Creek in Clearwater County are known for Sapphire sightings.
There have also been sapphires found in Valley County along the east side of Brundage Mountain west of McCall and the Rocky Flat area near New Meadows.
In general, sapphire occurrences are limited in Idaho, but just across the continental divide in Montana there are many world-famous sapphire deposits that may be worth researching if you are serious about finding the gem.