Monday, December 2, 2013

Gems of the Smithsonian I

The Bismarck Sapphire Necklace is a sapphire necklace designed by Cartier in 1935.

It is named after Countess Mona von Bismarck, who donated the piece to the Smithsonian in 1967. The sapphire itself was purchased by the Countess in Sri Lanka in 1926, during her honeymoon with Harrison Williams. The necklace consists of a single chain of platinum links connected by pairs of round brilliant cut diamonds. The 98.6-carat (19.7 g) table-cut Bismarck Sapphire is mounted in a pendant at the front of the necklace, surrounded by baguette-cut diamonds and eight smaller square-cut sapphires placed symmetrically around the edges of the setting.
The Carmen LĂșcia Ruby is a 23.1-carat Burmese ruby. Set in a platinum ring with diamonds, it was donated by businessman and philanthropist Peter Buck in memory of his wife Carmen LĂșcia. The stone was mined from the Mogok region of Burma in the 1930s. While sapphire, emerald and diamond gems weighing hundreds of carats exist, high quality Burmese rubies larger than 20 carats are exceedingly rare.
The Blue Heart Diamond was found at the Premier Mine, South Africa in 1908. This 30.62 carat heart-shaped, brilliant cut blue diamond was faceted by French jeweler Atanik Eknayan of Paris in 1909-1910 from a 100.5 carat piece of rough.

Mrs. Marjorie Merriweather Post gifted the Blue Heart Diamond to the National Gem Collection in 1964.
The DeYoung Red Diamond is one of the largest known natural fancy dark red diamonds. It is a modified round brilliant cut diamond that has a clarity grade of VS-2 and weighs 5.03 carats. The diamond was acquired by S. Sydney DeYoung, a Boston jeweler, as part of a collection of estate jewelry in which it was wrongly identified as a garnet. It was gifted to the National Gem Collection by Mr. DeYoung in 1987.
This 75.47-carat Colombian emerald was once the property of Abdul Hamid II, Sultan of the Ottoman Empire (1876-1909), who according to legend, wore it in his belt buckle. Tiffany & Co. purchased the emerald at auction in 1911 and initially set it into a tiara, featured in the New York World’s Fair “House of Jewels” exhibit in 1940. In 1950, it was mounted in its current brooch setting and was featured on the first page of the Tiffany Christmas catalogue. In its platinum setting, the Hooker Emerald is surrounded by 109 round brilliant and 20 baguette cut diamonds, totaling approximately 13 carats. The Hooker Emerald is a beveled square-cut gem that exhibits exceptional color and clarity for an emerald of its size. The stone originated from the famous mines of Colombia and probably was shipped to Europe by Spanish conquistadores in the 16th or 17th century. Mrs. Janet Annenberg Hooker purchased the brooch from Tiffany in 1955, and in 1977 she donated it to the Smithsonian.
The 58.19-carat Maharani Cat’s Eye from Sri Lanka is one of the finest gems of its kind. The optical phenomenon of chatoyancy can be displayed by many gemstones, but the most popular and highly prized is that of the mineral chrysoberyl. Chatoyancy is light reflected off of parallel inclusions of microscopic tubes or crystals of another mineral inside the gemstone. When a stone is cut with a domed top and flat bottom, called a cabochon, the reflected light is focused into a bright band that forms the “eye.” In fact, the term “Cat’s Eye” is synonymous with chrysoberyl, owing to the resemblance of the phenomenon with the slits of cat’s pupils. The “eye” that the stone displays when it is cut en cabochon is caused by the reflection of light off numerous parallel inclusions of fine, needle-like crystals, commonly of the mineral rutile.