|point naif Polar Star Diamond|
|Written by Administrator|
|Sunday, 23 September 2007|
point naif (pronounced "knife"). A
term used by Tavernier in the 17th century to indicate a diamond octahedron or other crystal shape having easily distinguishable natural faces. However, the term natural
point is now used in the industrial-diamond industry to mean an elongated diamond crystal, particularly one with sharp points. See naif. polariscope. An optical instrument that consists basically of two polarizing filters. The filter through which light enters is called the polarizer; that through which observations are made is called the analyzer. The instrument is used to ascertain whether a gemstone possesses single or double refraction. It is also used to detect anomalous double refraction, which, when found in a singly refractive stone such as diamond, often indicates internal strain. See isotropic,
ANISOTROPIC, ANOMALOUS DOUBLE REFRACTION, REFRACTION, INTERNAL STRAIN.
Polar Star diamond. In layman's language, the 41.36-carat Polar Star has been described as the "brightest" diamond ever seen — a stone of incomparable beauty and luster. Very little is known of its background, although it is thought to be of Indian origin. It is said to have belonged to Joseph Bonaparte, eldest brother of Napoleon I, who reputedly paid $10,000 for it. Joseph was King of Naples from 1806 to 1808, King of Spain from 1808 to 1813, and lived in the United States from 1815 to 1841. In the 1820's, the Polar Star was sold into Russia. Prince Yous-soupoff, who was living in France in 1949, stated at that time that the gem had been owned by his family for more than 100 years but was later sold to Carrier of Paris. It is now the property of Lady Lydia Deterding, Russian-born former wife of the late oil magnate, Sir Henry Deterding. The Polar Star is presently set in a ring, but detaches to form a pendant. Alternate name: Youssoupoff Diamond.
Pole Mine. An early diamond pipe mine in the Kimberley, Republic of South Africa area, located north of the city of that name.
polish. The relative smoothness of a surface, or the degree to which the finish of the surface approaches optical perfection. A well-polished diamond shows no wheel marks or other surface blemishes under 10x.
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