The term Jade is generic; it actually refers to three minerals - Jadeite, Nephrite, and Chloromenlanite. “Nephrite”, commonly referred to as Jade, was adopted as Wyoming's official gemstone on January 25, 1967. This same Jade was adopted as the State gemstone by the Alaska Legislature in 1968.
The famed Wyoming jade fields occur in a rectangular band that runs roughly from Lander southwest to Farson, down to the Red Desert in Sweetwater County, east to Seminoe Dam, north to Alcova, and westward back to Lander. Wyoming jade is black, olive green, emerald green, light apple green and sometimes gray to white. The lighter colors of jade, especially apple green, are most in demand for gemstones. Today, most people believe that Wyoming's jade fields have been scoured so thoroughly by six decades worth of jade hunters that the light green variety of nephrite can no longer be found.
Most deposits of Jade are found near the Kobuk River. Alaska has large deposits including an entire mountain of jade on the Seward Peninsula, called Jade Mountain. It can also be found near the Dall and Shungnak rivers. This famous, remote, Arctic jade has an extensive history. Artifacts made from Kobuk River nephrite are hundreds of years old and have been found at archaeological sites along the Bering and Pacific coasts of Alaska and British Columbia, and the Arctic coast of Canada. The quality of Alaskan nephrite is highly variable; the finest material is usually found in smooth, stream-rolled boulders. Many of the boulders are covered by a thin rind of brown material, a result of weathering, which must be removed to reveal the unaltered green nephrite beneath.