Yogo Gulch, Montana, Sapphires Most Yogo Gulch sapphires are not very big, but their color and clarity are exceptionally fine. The majority of the crystals are tabular in shape and will cut stones less that 0.2 carats in size. Although some crystals display a more or less purplish-hue, on average, the color is a fine cornflower blue. The Yogo Gulch deposit is unusual in that most of the sapphires are actually gem quality; they contain very few inclusions. Most sapphire crystals from other world locations are subjected to all sorts of ultra-high-temperature heat treatments and surface diffusion methods to improve both clarity and color. Yogo Gulch sapphires don't require such human intervention. It is for this reason that the best faceted Yogo Gulch sapphires command a price similar to that of diamond. BACK