Whiteflash-Diamond Playground

From Science Daily - Shine a white light on the Hope Diamond and it will dazzle you with the brilliance of an amazing blue diamond. Shine an ultraviolet light on the Hope Diamond and the gem will glow red-orange for about five minutes. This phosphorescent property of blue diamonds can distinguish synthetic and altered diamonds from the real thing, and it may also provide a way to fingerprint individual blue diamonds for identification purposes, according to a team of researchers from the Naval Research Laboratory, the Smithsonian Institution and Penn State. Other colors of diamonds do not phosphoresce, but fluoresce, emitting visible light only as long as they are stimulated with ultraviolet radiation. Blue diamonds that phosphoresce emit light even after the ultraviolet lamp is turned off. Unlike the Hope, however, most blue diamonds produce a bluish light rather than reddish light. The red phosphorescence is rare enough that researchers thought that those blue diamonds that did glow red must have come from the parent of the Hope — an original 112-carat blue diamond mined in India in the mid-1600s. That diamond was cut down to 67 carats to become the French Blue owned by French kings and, after being lost during the French Revolution, appeared 20 years later in 1812 as the 45-carat stone known today as the Hope Diamond. The research, recently reported in the journal Geology, confirms that all blue diamonds have a red phosphorescent component and that, through spectroscopic analysis, each blue diamond can be individually identified. “The Hope Diamond is the most popular museum object in the world,” says Peter J. Heaney, professor of geosciences at Penn State. “Even so, the Smithsonian considers the specimens in the museum objects of scientific value. They have an enormous number of gemstones in their collection and they encourage scientific research to figure out how the stones formed, and what gives them their special properties.”