Exceptional Rough and Cut Blue Sapphire from Rock Creek, Montana
The Rock Creek sapphire deposit in Montana has been active since the 1890s and is known as the state’s most fruitful deposit (T. Hsu et al., “Rock Creek Montana sapphires: A new age of mining begins,” https://www.gia.edu/ gia-news-research/rock-creek-montana-sapphires-new-age-mining-begins, August 29, 2016). This year in Tucson, Jeffrey Hapeman of Earth’s Treasury showed the authors a very fine untreated blue sapphire rough with a yellow spot in the center, as well as a top-quality faceted light teal blue untreated stone with some yellow zoning (see above). Since 2014, Mr. Hapeman has been focusing on Rock Creek material in these nontraditional lighter blues to greens. They have proven to be very popular, as several AGTA vendors this year reported strong demand for these colors, not only in Montana sapphire but from other sources as well. When it comes to unheated material, only about 5% of the rough from Rock Creek is cut without treatment, and most of these are either fancy pinks, yellows, or lighter blues. In the past year Mr. Hapeman has seen a shift in demand to parti-colored and green sapphires, particularly deep bluish green.
