Montana Sapphires - The story of America's Gemstone

By Rowena Murray

Edited by Amy Pettifer

Thirty years later another gold miner, Jake Hoover, began to work the gravels of the Judith River in the Yogo Creek area of the Little Belt Mountains. In the first year of prospecting, Hoover and his colleagues found a mere 40oz of gold (equal to about $700) alongside a mass of translucent blue pebbles. Curious, Hoover packed up the stones in an old cigar box and sent them to the famous gemologist George F. Kunz who correctly identified them as sapphires. Kunz was so impressed with their natural blue color and excellent clarity that he called them, 'by far the most important precious stones mined in the United States'.

Hoover was sent a check for $3,750 and Tiffany & Co.'s designers set to work on the 'home-grown' gems.

Tiffany & Co had previously produced a brooch using Missouri River sapphires in the form of a crescent, but with the discovery of the Yogo stones came the design and manufacture of one of the most iconic pieces of jewelry in Tiffany's history: the 'Iris Corsage' designed in 1900 by George Farnham.

Set with Yogo sapphires on the petals and demantoid garnets on the leaves, this exquisite piece of naturalistic design - too precious to be worn - showcases sapphires' cornflower hue to great effect. It was exhibited at the Paris Exposition Universelle in 1900, winning a gold medal for the firm.

Before Hoover's discovery, the most prominent sapphires in the trade were the fine 'cornflower' blue stones of Kashmir, the richly saturated material of Burma, and the light-toned stones of Ceylon (Sri Lanka). The term 'cornflower blue' is recognized throughout the gem trade as representing the finest hue available in sapphire, however other factors such as intensity of color and the lightness or darkness of the gem material are also vital in appraisal.

Despite their delicate and utterly unique spectrum of colors - spanning glassy blues, mossy greens and brilliant yellows - Montana Sapphires are deemed less precious than their international counterparts, and would ultimately experience mixed fortunes. The majority discovered were either too pale or too small to cater to the tastes of the time and the high cost of their mining made it difficult to meet commercial demand. Early Yogo supplies were even marketed in Europe as 'Oriental' sapphires, owing to their subtle color, which could pass for the better known pale blue Ceylon.

At the turn of the century, the Yogo mines produced roughly 13 million tons of rough sapphires which were used both in jewelry and as abrasives and bearings in watch mechanisms. However, the introduction of synthetic sapphires in the 1920's dramatically lowered the demand for natural rough stones which, combined with the outbreak of WWI and the Great Depression, meant that interest in the mines began to wane. In 1923, a huge flash-flood destroyed much of the mining equipment and production struggled to recover.

While they may have struggled to attain any great commercial success, the Montana reserves remain a source of fascination for gemologists and enthusiasts to this day.

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- Considered to be the biggest in size (up to 10ct) with a light blue to green-blue color

- Today, the only mining being conducted is by small individual companies along the Missouri River, including Gem Mountain which operates as a 'fee-digging' area, where visitors can purchase gravel onsite and sift for the gems

- Generally smaller (1ct or less) but more abundant, occurring in an array of colors from pinks, yellows, greens and oranges

- Very similar to the Rock Creek variety, but less numerous