Sapphires from Montana
Although sapphires have been found in several locations in the United States, including Alaska, Alabama, Colorado, Georgia, Idaho, Indiana, Iowa, New Jersey, North Carolina, Pennsylvania, and Washington, the most famous of these locations is the state of Montana. Although sapphires can be found throughout Montana, the majority of the finds can be attributed to four major locales: Yogo Gulch, Rock Creek, Dry Cottonwood Creek, and the gravel bars along the Missouri River northeast of Helena.
Sapphire production in Montana was, at least initially, a byproduct of the gold rushes of the 1860s. Early prospectors searching for gold in the gravel of the Missouri River discarded the annoying blue pebbles that continually clogged their sluices. The discovery that these stones had value is attributed to Ed “Sapphire” Collins who forwarded samples to Tiffany and Company in 1865.
The Missouri River, Rock Creek, and Dry Cottonwood Creek deposits are associated with high yields of high-clarity fancy sapphires, with colors ranging from light pinks, purples, oranges, yellows, and greens, to pale blues. Although the sapphires from these three locations have similar color ranges, each site has distinct crystal sizes, morphology, and trace element composition. Initially, these three deposits were worked primarily for industrial purposes, and when synthetic sapphires flooded the market in the 1940s, production declined. Today, advances in heat-treatment technologies have produced renewed interest in sapphires from these locales, although the cost of labor, heavy environmental regulation, and a short mining season have discouraged large-scale exploitation.
As gold production flagged in Yogo Gulch, it was abandoned by prospectors despite the large numbers of “blue wafers” found in the gravel. Although stories differ, it is generally believed that a rowdy miner named Jake Hoover collected a number of the stones and dispatched them to Tiffany and Company in 1895 in a cigar box. When Tiffany purchased the lot for $3,750 and declared that the stones were “sapphires of unusual quality,” a small scale sapphire rush began. A year later, the source of the sapphires, an igneous dike about five miles in length, was discovered by a part-time prospector and sheep farmer, John Ettien. The “cornflower blues” of Yogo Gulch attracted considerable attention and funding from both domestic and foreign mining companies. A British company controlled the mine for some thirty years, which is why Yogo sapphires can be found among the British Crown Jewels.
Untreated Yogo sapphires are famous for their excellent blue color and exceptional clarity; and many believe their natural qualities surpass heat-treated stones from all over the world. However, their primary drawback is their small size. Cut gems from Yogo Gulch are very rarely more than one carat in size.