Most Americans don't realize that exquisite sapphires have long been mined from gravel bars and intrusive dikes in the state of Montana. There are several reasons for this. First, the color of most of these stones isn't the typical deep blue of stones from Sri Lanka, Myanmar, or Australia. Second, although there has always been the potential for large-volume mining, the Montana localities have rarely been exploited on a large scale (Perhaps because of the cost of labor in this country).
Whatever the reasons, Montana produces sapphires as fine as any in the world. Not far from Utica, Montana, a sapphire-producing lamproite dike cuts through the country rock for almost five miles. Discovered by a prospector, Jake Hoover, in 1895, the Yogo Gulch mine went on to produce hundreds of thousands of carats of exquisitely-clean blue gemstones
But Montana has many sapphire locations. Most are alluvial deposits, such as those along the Missouri River near Helena (The El Dorado Bar Locale), or Dry Cottonwood Creek near Butte. Currently, the largest sapphire production is coming from the Gem Mountain area near Philipsburg. The Gem Mountain stones display a remarkable range of colors including blue, green, pink, and gorgeous yellows and oranges. Further stimulating sapphire mining in Montana is the application of advanced heat-treating technology that can remarkably improve the clarity and color of many Montana stones (Don't get upset: heat treatment has long been a standard practice in Thailand to turn ugly Sri Lankan gueda sapphire into fine blue gem material. Consult our links to the ICGA and other websites to learn more about gemstone treatments).
In the past, many of the Montana mines have been open to amateur collectors on a fee basis, and many fine stones were found. Unfortunately, because so few of these stones have reached the American jewelry market, many Americans feel these stones aren't true sapphires or are somehow inferior to gems from the orient. The beauty of these stones will eventually dispel that misconception.
As of this writing, 2012, El Dorado Bar sapphire mine was not open to the public on a fee basis. Those wishing to collect/mine sapphire in the Helena area should contact the local chamber of commerce to check on the status of the various sapphire mines in that area. In the past, there have been other sapphire mines either selling buckets of gravel concentrate, or allowing digging/screening/washing of alluvial sapphire-containing material.