A rancher posted a cigar box of blue pebbles to an assay office. It reached Tiffany's, where the appraiser called them the finest precious gemstones ever found in the United States.
Yogo sapphires come from Yogo Gulch, part of the Little Belt Mountains in Judith Basin County, Montana. They are cornflower blue, coloured by trace amounts of iron and titanium, with high uniform clarity, and unusually they keep their brilliance under artificial light instead of going flat the way many sapphires do.
Nobody knew what they were at first. Gold was discovered at Yogo Creek in 1866, and by 1878 miners had noticed blue pebbles sitting in the stream alluvium alongside the gold. It took until 1894 for anyone to recognise them as sapphires. Mining began in 1895, after the rancher Jake Hoover sent his cigar box off and got Tiffany's verdict back. Hoover bought the original mother lode from a sheepherder and later sold it on to investors. It became the English Mine, which flourished from 1899 into the 1920s. A second working, the American Mine, took the western section of the dike and never made money.
The geology is why this has never become an industry. The sapphires sit inside a vertically dipping resistive igneous dike, so the rock is hard and the mining awkward, and effort here has been sporadic and rarely profitable for over a century. A flash flood in 1923 destroyed the mine structures and effectively ended the first era. In the early 1970s California investors started Sapphire Village, a small development where property owners could prospect their own lots. The Vortex Mine opened in 1984 and turned a profit for a few years on two underground sapphire-bearing dikes, then closed in 2004 because the dike rock was simply too hard to free the stones from economically. Mike Roberts took it over in 2008, having given up gold mining in Alaska, and works it from the 300-foot level. No mine water leaves the site.
An estimated 28 million carats are still in the ground. Yogo stones went to First Ladies Florence Harding and Bess Truman and several sit in the Smithsonian collection, but the promoters' stories putting them in the crown jewels of England or Princess Diana's engagement ring are dubious.
It is PRIVATE and not open to the public, and there is no casual collecting; this pin marks the story and the ground.
Yogo sapphire (cornflower blue)
Other places on the map within a couple of hours.
