Fancy Vivid yellow Radiant diamond 7.17 x 4.76 x 3.54mm.
GIA Certificate 1.09 carats.
The Tiffany Yellow Diamond is one of the largest yellow diamonds ever discovered; it weighed 287.42 carats (57.484 g) in the rough when discovered in 1878 in the Kimberley mine in South Africa, and was cut into a cushion shape of 128.54 carats (25.108 g) with 82 facets—24 more than a traditional round brilliant—to maximize its brilliance. The facet pattern features eight needle-like facets pointing outward from the culet (bottom) facet. Jewellery and diamond historian Herbert Tillander refers to this as a 'stellar brilliant cut', and lists the gem in his book "Diamond Cuts in Historic Jewelry - 1381 to 1910" (1995) among other such diamonds: The Koh-I-Noor, the Polar Star, the Wittelsbach, among others.
Discovered in South Africa in 1877, the stone was purchased by New York jeweller Charles Tiffany. His gemmologist, George Frederick Kunz, studied the gem for a year before beginning to cut it; reducing it from 287 carats (57.5g) to its current size. The cutting was carried out in Paris. Kunz was a mere 23 years old at the time. It was mounted by Jean Schlumberger.
In 1879, the Tiffany branch in Paris obtained the Tiffany Diamond, which weighed 287.42 carats in the rough. It was the largest yellow diamond found up to that time. The formidable task of supervising the cutting of this extraordinary stone was the responsibility of one George Frederick Kunz (1856-1932), a twenty-three year old gemologist who had just joined the firm. The cutting process took exceptional courage and insight. Kunz added an additional 32 facets to the accepted square antique brilliant cut, bringing the total to ninety. The result is an exceptionally scintillating cut which returns a great deal of light to the eye. Large diamonds of comparable brilliance were not fashioned until well into the 20th century.
The gem was on loan from Tiffany & Co. to the Smithsonian National Museum of Natural History in Washington D.C. and was on display from April 18th, 2007 until September 23rd, 2007. At the time, Jeffrey E. Post, the museum`s gem curator, said that this was the largest diamond on display in the U.S. The famous Hope Diamond is only 45.5 carats, which is two and a half times less than the Tiffany Yellow Diamond.
The diamond is known to have been worn by only two women during its lifetime. It was worn by Mrs. Sheldon Whitehouse at the 1957 Tiffany Ball held in Newport, Rhode Island, mounted for the occasion in a necklace of white diamonds. It was subsequently worn by Audrey Hepburn in 1961 publicity photographs for Breakfast at Tiffany's.
In a Yellow diamond, a few carbon atoms per million have been replaced by nitrogen atoms, each containing five valence electrons. The structure of the diamond crystal does not change significantly, but the extra electrons occupy a donor level.The nitrogen donor level energy in a diamond is large, peaking at about 4 eV. With a concentration of a few nitrogen atoms per million, instead of a clean "spike" donor level energy, the nitrogen donor level energy broadens into a band because of a number of complex factors, including thermal vibrations. This broadened donor energy band results in the difference between donor and conduction bands being as low as 2.2 eV. The most likely transition allows incident light with energy of 4 eV per photon to excite electrons from the donor level to the conduction band. However, it is possible for electrons to be excited to the conduction band with energy of 2.2 eV and upwards. This means that blue and violet light are absorbed from the full spectrum of light normally transmitted, and the resulting colour is yellow.