10K White Gold Promise Ring with a Blue Diamond Center Stone and White Diamond Side Accents. Natural untreated blue diamonds do exist, such as the Hope Diamond, they are extraordinarily rare and very expensive. SuperJewelers blue diamonds are safely irradiated in a cyclotron or linear accelerator, followed by a heat treatment, that turns brownish and pale yellow diamonds into richly colored, affordable blue diamonds. This color change to blue is permanent, but can change if the diamond is exposed to high heat. SuperJewelers blue diamonds are beautiful and safe to wear. For sizing info check here!