Tiffany stone is a rare material. It is mined at one location worldwide – the Brush Wellman beryllium mine, at Spor Mountain, western Utah. It occurs there as nodules that are part of the ore produced at the mine. The nodules typically contain between one and two percent beryllium by weight.
The United States Geological Survey reports that the nodules are carbonate clasts that have been largely replaced by fluorite. Small amounts of bertrandite, a beryllium mineral with a chemical composition of Be4Si2O7(OH)2, occurs as submicroscopic grains within the fluorite.
Almost all of the Tiffany stone mined at Spor Mountain is crushed and used to produce beryllium. A small amount has been carried out of the mine by employees, and a small amount has been gathered by collectors who have rarely been allowed into the mine. These are the only sources of the gem material because Brush Wellman has always been interested in producing beryllium and has not been interested in Tiffany stone.
Utah Tiffany Stone: “Tiffany Stone” is an unusual material found as mineralized nodules in a beryllium tuff at the site of the Brush-Wellman beryllium mine. It is thought to be an opalized fluorite. Tiffany Stone is also known as “bertrandite” and “ice cream opal.” It is a rare material found only at the Brush-Wellman location.