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RAL PDF Print E-mail
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Monday, 29 October 2007

RAL. Acronym for Reichs-Ausschuss fur Lieferbedingunger and Gutesich-erung beim DNA, the German Standards Association Commission on diamond grading standards and nomenclature.

 
Rajah Diamond PDF Print E-mail
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Monday, 29 October 2007

Rajah diamond. Reported to be one of two large Diamonds (the other being the Light of India diamond) that belonged to the late Boston socialite, Mrs. Jack Gardner. The stones were purchased from Tiffany'sin 1886 and according to the bill of sale they weighed 25.5 carats and 12.38 carats. Unfortunately, the bill did not specify which diamond had which weight. Owned by another Bostonian; name undisclosed. See

LIGHT OF INDIA diamond.

 
Rainbow Diamond PDF Print E-mail
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Monday, 29 October 2007

"Rainbow diamond." A misleading trade name for synthetic rutile.

"Rainbow Gem." A trade name for synthetic rutile.

"Rainbow Magic diamond." A mis­leading trade name for synthetic ru­tile.

 
radius-dressing diamond tool PDF Print E-mail
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Monday, 29 October 2007
radius-dressing diamond tool. A single-diamond dressing tool for dressing radial forms in grinding wheels.
 
radium-treated diamond PDF Print E-mail
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Monday, 29 October 2007
radium-treated diamond. A diamond whose color has been changed (usu­ally to greenish) as a result of being exposed to the radioactive emana­tions of radium salts. Because of the prolonged radioactivity of Diamonds thus treated and consequent danger of injury to the finger of the wearer, this form of color alteration is not practiced commercially.
 
radioisotope PDF Print E-mail
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Monday, 29 October 2007

radioisotope. An unstable isotope of an element that decays or disinte­grates spontaneously, emitting radi­ation. Radioactive cobalt, cobalt-60, is one of the most common radioisotopes with a half-life of 5.3 years; radiation, beta and gamma. Cobalt-60 emits gamma rays which have about the same penetrating power as those of radium. Used for color treating Gemstones.

 
quarter quasima diamond Quebec diamond Queen Elizabeth Pink Diamond PDF Print E-mail
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Sunday, 23 September 2007

quality, factors that determine. The quality of a diamond can be rated only when the following factors have been analyzed: carat weight; propor­tions and finish (cutting); clarity, or imperfection, grade; color grade; and shape, or style of cutting. See

CUTTING; CLARITY OR IMPERFECTION GRADE; COLOR GRADE; FINISH; SYMMETRY; PROPOR­TIONS; PROPORTIONS, GOOD.

quarter. A common abbreviation for a quarter carat.

quartz. Silicon dioxide (SiCh), hexa­gonal, hardness 7, S.G. 2.65, R.I. 1.544-1.553, birefringence 0.009, dispersion 0.013. One of the most common and widelydistributed minerals. Sometimes used as a dia­mond simulant.

quasima diamond. A misnomer used in Arabia for rock crystal.

Quebec diamond. A misnomer for rock crystal.

Queen Elizabeth Pink diamond. See

WILLIAMSON diamond.

Queen Frederica diamond. An en­graved, wafer-thin, colorless dia­mond, weighing slightly less than two carats and measuring 7 x 10 mm. It bears the portrait of Frederica Louisa Wilhelmina, wife of William I, Prince of Orange and the first king of the Netherlands. She was the great-great grandmother of present Queen Juliana. The stone is owned by Max Fine & Sons, Inc., New York City, in which family it has been since 1920.

Queen of Albania diamond. Repor­tedly, this 49.03-carat pear-shape be­longed to Geraldine, Queen of Albania and was put up for auction at Christie's, London, in 1960. How­ever, bids were below the acceptable minimum and Christie's bid in at $182,000 to protect the owner. Its ownership and whereabouts are un­known today. Some gem historians speculate that the Queen of Albania is the P/'gott.

Queen of Belgium diamond. This 40-carat emerald-cut diamond was

formerly a 50-carat cushion-shaped stone that belonged to Queen Marie Henrietta of Belgium, wife of King Leopold II. It had been given to her by her mother, the wife of Archduke loseph, Palatine of Hungary. In its 40-carat version, the Queen of Bel­gium was once handled by Harry Winston, New York City gem dealer, but its present location and owner are not known. Alternate names: La Reine diamond, La Reine Des Beiges diamond, and Des Beiges diamond.

Queen of Holland diamond. A 136.25-carat cushion-cut brilliant, described as an "intense blue." It was cut in Amsterdam in 1904 and was owned there for many years by the firm of F. Friedman. In 1925, it was exhibited at the Paris Exposition of Arts and Industry. Later, it was sold by a Paris jeweler to an Indian maharaiah for an estimated $1,000,000. The present whereabouts of this diamond are not known. Queensland. See Australia

 
pure purest water Putfontein Pypklip PDF Print E-mail
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Sunday, 23 September 2007

pure. A rarely used term that refers to comparative perfection; more or less synonymous with clean

. purest water. A little-used quality des­ignation for highly transparent dia­monds of fine color. See water.

Purnendu diamond-Mining Works. A diamond-mining company in the Panna district, Madhya Pradesh, In­dia. See india.

Puruni River. A source of Diamonds in Guyana, formerly British Guiana.

See GUYANA.

Putfontein. A minor alluvial dia­mond deposit in the Lichtenburg area, Transvaal Province, Republic of South Africa.

Pypklip. One of the more important alluvial diamond deposits in the Lichtenburg area, Transvaal Province, Republic of South Africa. Production figures from this area for one recent year credited Pypklip with approxi­mately 2050 carats.

pyrope. This species of the garnet group is used as an indicator of the presence of Diamonds. It is resistant to wear and can survive being trans­ported many miles from its source
 
Progress Diamond proportion of diamonds to blue ground proportions ProportionScope Punch Jones Diam PDF Print E-mail
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Sunday, 23 September 2007

Progress diamond. An 80.66-carat rough diamond found in the Mir pipe. Now in the U.S.S.R. diamond Fund in Moscow.

proper proportions (of a diamond).

See AMERICAN CUT; TOLKOWSKY, MARCEL; PRO­PORTIONS; PROPORTIONS, GOOD.

proportion of Diamonds to blue ground. See richness of maior diamond

DEPOSITS, RELATIVE.

proportions. A term that meant orig­inally the distribution of the mass of a fashioned diamond above and below the girdle. Use by diamond men has broadened its meaning to include the major factors that deter­mine cutting quality; i.e., total depth as a percentage of the girdle diame­ter, table diameter, girdle thickness, facet angles, symmetry, and even de­tails of finish. See proportions, good;

CUTTING; AMERICAN CUT; TOLKOWSKY, MARCEL; FINISH; SYMMETRY.

ProportionScope. A diamond-grading instrument designed and first manufactured by the Gemological Institute of America in 1967. It is an optical comparator for the checking of the proportions of a brilliant. It combines lenses and movable mir­rors to project the silhouette of a dia­mond on a screen. Line diagrams of Tolkowsky proportions on the screen, as well as a "zoom" range, enable

proportions, good. The proportions derived mathematically for the op­timum treatment of light are seldom cut today. Present tastes among jewelers apparently have been con­ditioned somewhat by the weight saving and cost reduction made pos­sible through "spreading," for slightly larger tables and thinner crowns. However, there is general agreement that the angles of the Tolkowsky Theoretical Brilliant Cut are op­timum, so any stone of good propor­tions should have a 403/4° pavilion angle, 34 Vi" crown (bezel), (and a girdle of medium thickness). See

AMERICAN CUT, SPREAD STONE, SWINDLED STONE, PROPORTIONS.

Province of the Cape of Good Hope (also called Cape Province or the Cape). A province in the Republic of South Africa, the north-east and east-central portions of which have been, and are, important diamond-producing areas. The famous mining town of Kimberley is in Cape Prov­ince near the boundary of the Or­ange Free State.

puinwassers. A term used to describe washers of old tailing (waste washers) in the South African dia­mond fields. pulsator jig. See jig.

Punch Jones diamond. One of the largest United States Diamonds, this 34.46-carat greenish-gray crystal was found in 1928 on Rich Creek near Peterstown, West Virginia. It was dis­covered by Grover C. Jones and his son, William R "Punch" Jones, while playing horseshoes but was not posi­tively identified as a diamond until 1943, when it was examined and tested by Professor Roy J. Holden of Virginia Polytechnic Institute. It is now on permanent display in the Smithsonian Institution, Washington, D.C.

 
Princess Mathilde Diamond Princie Diamond Prinz cut profile cut PDF Print E-mail
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Sunday, 23 September 2007

Princess Mathilde diamond. Mathilde was the cousin of Louis Napoleon (later Napoleon III of France) and hostess for him until his marriage to Eugenie de Montijo; this diamond is thought to have been named for her. Mathilde, who was married to Prince Anatole Demidoff of Russia, had magnificent jewels. Later, the diamond was also said to have belonged to the great collector, Abdul Hamid II, Sultan of Turkey. Still later, in 1933, it was sold to an undisclosed buyer in Paris by the Monte de Piete (National Pawnshop), which described it as "a brilliant of 16.25 carats and of a special shape that closely resembles the hexag­onal."

Princie diamond. The Princie Dia­mond, which apparently has no pre­viously recorded history, is thought to have belonged to the Nizam of Hyderabad at one time. It is a pink, cushion-cut stone of 34.64 carats. In 1960, it was sold at auction by Sotheby's to the London branch of Van Cleef & Arpels for $128,000 and sent to their Paris store. In the same year, it was christened the Princie at a party in its honor in Paris. Among the guests were the Maharanee of Baroda and her fourteen-year-old son, the prince heir, whose pet fam­ily name is "Princie." Van Cleef's be­lieve it to be one of the largest and finest pink Diamonds in the world; it is mounted as a pendant and sur­rounded by large white brilliants on a slender necklace of baguettes.

Prinz cut. A small, simple polished 5 faceted octahedron.

proclaimed area. A term used in the Republic of South Africa for diamond-bearing claims or land that have been proclaimed by the government-owner for the issuance of digger's licenses. See deproclaimed

AREA, RESTRICTED ALLUVIAL DIGGING.

profile cut. A diamond cut invented in 1961 by Mr. Arpad Nagy, founder of the diamond Polishing Works in London. The cut makes economical use of flat crystals in order to provide a large surface area of diamond at a low cost. It was initially called the

Princess cut. Flat crystals are gang-sawed into parallel plates about 1.5 mm. thick. The plates are then cut into a variety of desired shapes and the top surface polished. A series of narrow parallel grooves are cut on the bottom of each plate which gives the required total internal reflection to make it lively, but it lacks fire. See

Princess CUT.

Last Updated ( Sunday, 23 September 2007 )
 
premium prices Presidente Dutra Diamond Getulio Vargas Prince Edward of York Diamond PDF Print E-mail
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Sunday, 23 September 2007

premium prices. (1) Prices above the normal trade prices that are asked for certificated stones. These prices,however, do not apply to all dia­monds with certificates. Premiums are only paid for Diamonds of certain grades and sizes. (2) Premium prices also refer to percentages over theDiamond Trading Company's list price on "original" series from DTC.Thus, a premium of 5% means theprice is 5% over the DTC selling
price.

Presidente Dutra diamond. A 409c arat diamond that was found in 1949 by a prospector in the ouradinho River, Coromandel district, Minas Gerais, Brazil. From it were cut 36 stones totaling 136 car ats, the largest of which weighed 9.60 carats and the smallest, .55 car ats. Also called the Dutra diamond.

the San Antonio River, municipality of Coromandel, Minas Gerais, Brazil, by a native prospector and his part­ner, a farmer. It was named in honor of the then president of that country,


Getulio Vargas. The partners sold the stone to a broker for about $56,000 and it changed hands several times, eventually reaching a reported value of $235,000. Harry Winston, New York City gem merchant, bought the stone in 1939 for approximately $600,000. In 1941, Winston had it cut into 29 stones, the important ones of which were all emerald cuts. The largest of these, which weighed 48.26 carats, is known as the Vargas or Presidente Vargas diamond. It was owned for a number of years by Mrs. Robert W. Windfohr of Ft. Worth, Texas, but later came back into the possession of Harry Winston. Own­ership of the other stones is not known Presidente Vargas diamond. With a weight of 726.60 carats, the Pres­idente Vargas diamond qualifies as one of the largest Diamonds ever found. It was discovered in 1938 in

Prince Edward of York diamond. A

60.25-carat, fine-quality, pear-shaped African stone that was imported to the United States in 1901 by Alfred H. Smith & Co. and sold to a New York banker. Ultimate disposition unknown.ž

Princess cut. An earlier name for the profile cut invented by Arpad Nagy in 1961. Also applied, for a time at least, to the 144-facet round brilliant. See profile cut.

 
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