The 31.06 carat, rare grey-blue Wittelsbach-Graff Diamond is set to make its exciting first public appearance in half a century on January 28, 2010. The spectacular diamond was last displayed in 1958 at the Brussels precious gemstone exhibition. The National Museum of Natural History announced that it would add the blue diamond to its precious gemstone exhibition, which already includes the famed Hope Diamond. The two rare blue fancy colored diamonds will both be displayed in the same gallery so as to allow visitor’s the opportunity to compare and contrast between the two gemstones.

The Wittelsbach-Graff Diamond’s origins can be traced back to 1664. The diamond made its first appearance in historical records which detailed the betrothal of Princess Margaret Teresa of Spain to Prince Leopold I of Austria. The diamond was included in her dowry and remained in Austria after her death as part of the Austrian crown jewels. In 1722 the Wittelsbach diamond was relocated to Bavaria, where it was mounted onto a glorious crown which was to be worn by Maximilian IV Joseph von Wittelsbach, the first Bavarian king. The diamond remained part of the Bavarian crown jewels collection until 1921, when it was sold off to private collectors. The diamond was resold in 2008 at a Christie’s auction, for an amazing 16.5 million GBP, to Laurence Graff, a private diamond collector and chairman of Graff Diamonds International Corp.

The diamond is believed to have originated from the same Indian diamond mine that produced the celebrated Hope Diamond. Apparently, the mine is known for its high carat blue diamonds, which are exceedingly rare in terms of fancy colored diamonds. Fancy colored diamonds come in a rainbow of hues and tinges, ranging from light yellow to black. The colors present in these diamonds were created as a result of chemical impurities and structural defects which sometimes occur in the diamond’s crystalline structure.

The value of fancy colored diamonds depends not only on carat weight, cut and clarity, but also on color. Fancy colored diamonds are graded on a different scale than colorless diamonds. While colorless diamonds are rated from D to K, fancy colored diamonds are rated from ‘ Faint’ to ‘Fancy Dark’. Generally speaking, the more intense the hue of a fancy colored diamond is, the higher its value will be. Also, since fancy colored diamonds are so rare (the rarest diamond color being red) they are not commonly found in high carat weights.

The value of fancy colored diamonds may also fluctuate as a result of the diamond’s cut and its clarity. High clarity, high carat, intensely colored diamonds are incredibly rare and unique, which is why extra care and precision are needed when cutting the diamond. Fancy colored diamonds are often cut into a round brilliant shape, which is meant to maximize the diamond’s brilliance and its beautiful natural hue. However, it is not altogether uncommon for fancy colored diamonds to be cut into unusual shapes such as heart, star, emerald and princess shapes. Fancy colored diamond cuts are designed to enhance the precious gemstones’ beauty and value. Consequently, if the diamond had a high carat weight and was vividly colored (as in the case of the Wittelsbach-Graff Diamond and the Hope Diamond) its value would be astronomical.