Montana sapphires on display at GIA

An extraordinary collection of dazzling rough and faceted sapphires from the Rock Creek deposit in what is known as Sapphire Mountain near Philipsburg, Mont. is currently on display at the Gemological Institute of America (GIA). On loan from Fine Gems International, this assortment of fine sapphires is on display through Feb. 2003 in the Salvador J. Assael Grand Atrium of the Institute’s world headquarters in Carlsbad, Calif.

Sapphires are among the most colorful and revered gemstones in the world, and Rock Creek deposit is one of the few locations where they are found and mined in the western U.S. Commonly described as “Rainbow Over Montana,” the Rock Creek deposit has been mined for more than 100 years and has produced an enormous 190 million carats of gem-quality rough sapphires during the period 1906—1923 alone. Sapphire Mountain, also known as Gem Mountain, yields every known color of sapphire, varying from yellow, orange, and blue, to dozens of other colors.

Sapphires were first discovered in Montana by gold miners who noticed an assortment of small pebbles at the base of their sluices where the gold would typically collect. The stones were thought of as a nuisance because they cluttered the sluice box, and the gold miners would remove and discard the pebbles. It wasn’t until the late 1890s that they were determined to be sapphires.

Montana sapphires are found in two different types of geologic settings, the first type lies in hard rock dikes. The second type of setting is alluvial deposits, where sapphire pebbles are sorted from the layers of gravel in rivers.

GIA Museum Director Elise Misiorowski said, “What a rare privilege it is to be able to display to the public this stunning specimen of fine sapphires. If you have the opportunity to come to the Carlsbad area, this exhibit is not one to be missed.”