Distinctly Montana Magazine

D I S T I N C T LY M O N TA N A • S U M M E R 2 0 1 8 72 In January, 1984, four local residents, Lanny Perry, Chuck Ridgeway and their spouses, Joy and Marie, followed a wood cutting trail in the Little Belt Mountains on land once inhabited by the Piegan Blackfeet. The trail led them to a dike section that had been disregarded as not worth mining. They staked their own claims on the property and began to mine. This new area was called the Vortex Mine, and the mining was to be done underground. In time, they sank a shaft and discovered two different veins of Yogo-bearing ore. In 2005, Alaskan gold miner Mike Roberts was offered a trade. Lanny Perry, who now owned the mine, said he'd swap it straight across for Rob- erts' gold mine outside of Fairbanks. Done deal. Mike worked diligently in the mine reaching a depth of over 400 feet, all the while following a strong vein of Yogo sapphires. Tragically, on March 19th, 2012, Mike Roberts died in an accident while working underground in the mine. In August of 2017 Don Baide, owner of Bozeman's Gem Gallery, purchased the Vortex Claim and mining equipment from Mike's widow, Laurie. Work proceeded with the forest service and state mine officials on achieving high code and safety standards. This summer of 2018 is the first mining season under new ownership. The Vortex Mine is a hard rock, drill and blast operation, working at the 400 ft level. The new owners are exploring sections of the mine through new technology to extract Yogos from areas previously not able to be extracted. e cornflower blue Yogo sapphires are popular with jewelry makers, including Tiffany & Co., and Yogo gems have even earned entry into the permanent collection at the Smithsonian Institu- tion, which houses a 10.2-carat stone that is likely the largest Yogo sapphire ever cut. Geologists are unsure precisely why the sapphires found in the Yogo district are primarily a deep blue while gems found in other areas, such as along the Missouri River north or east of Helena, or near Rock Creek west of Philipsburg tend to be different colors or much lighter shades of blue. But the assumption is that sapphires get their color from impurities in the mineral corundum (Aluminum oxide) as it forms in cooling metamorphic rock. Metamorphic rock, you will recall from high school geology, develops from older rock that is pushed back down toward the mantle, where it is re-melted, a process that can dramatically change its crystalline structure. As those crystals of sapphire are forming, their color will vary accord- ing to which metals happen to be present in the vicinity. If there's iron around, for example, the sapphire is likely to be yellow. If there's titanium or vanadium nearby to work its way into the crystals, a darker sapphire is likely to develop. And because corundum tends to form in igneous rock—the kind that oozes from active volcanoes— the purest and brightest sapphires develop from igneous rocks that were reheated. Yogo sapphires formed some 450 million years ago. e size of the sapphires depends on the rate at which the reheated rock cools: the slower the cooling, the larger the gem. As Richard Gibson, a geologist from Butte puts it, "Yogos result from the luck of geology—just the right elements and just the right cooling history making a "Goldilocks" gem that is just about perfect." When the gold prospectors came through Montana starting in the early 1860s, they often encountered sapphires in their pans. Because they were fixated on finding the heavy nuggets of yellow metal that meant a quick fortune, for the most part miners regarded the gems as a curiosity more than anything else. All that changed in 1895, however, when Jake Hoover sold a handful or two of the little blue stones he'd found on a gold claim he was working in Yogo Gulch to Tiffany & Co. for $3750, a sum equivalent to about $100,000 in 2018. According to Gibson, a fellow named George F. Kunz , a gemologist who worked for Tiffany, had an inkling of the Yogo treasure for a while leading up to Hoover's discovery. Kunz had written a book, in fact, called Gems and Precious Stones of North America (1890) in which he discussed the lower-quality specimens found elsewhere along the Missouri. Hoover eventually sold the claim on which he had originally hoped to find gold for $5000, but British financiers who recognized its value as a sapphire producer soon acquired the property at a price of $100,000—that would be $2.8 million in today's money. Mike Roberts (left) and Don Baide Overhead view of the Vortex Mine

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