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Oval Elegance Ovalumpally Mine o overspread stonevergrowth oxidized crystal PDF Print E-mail
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Sunday, 23 September 2007

Oval Elegance (trademark). A 58-

facet oval cut marketed by the diamond-cutting firm of Lazare Kap­lan & Sons, Inc. It is claimed by the producer to enlarge the apparent size of a diamond and to produce more brilliance than other fancy cuts. See

OVAL CUT

oval marquise. A marquise cut in which the typical boat-shaped out-


line has blunted rather than pointed ends. See marquise.

Ovalumpally Mine. The name of an old diamond mine in the Madras dis­trict of India. Same as woblapally mine,

overblue. A term applied to a dia­mond that has a bluish cast in day­light; usually a fluorescent stone. See

FLUORESCENCE.

overgrowth. A thin coating of cal­cium carbonate found on some dia­monds that prevents them from adhering to the grease table. overspread stone. See swindled stone.

oxidized crystal. A diamond crystal that contains iron oxide. In some Diamonds, surface oxidization has probably taken place due to contact with the atmosphere during forma­tion of an alluvial deposit. The ox­idized substance is usually yellow, orange or red, and its presence often imparts a false color to the crystal. In some other Diamonds the oxidation is nearly always inside the crystal; it is very seldom a coating. See star of

SIERRA LEONE diamond.

oyster line. See namaqualand.

Ozark diamond Company. One of

the companies that was organized to mine the Arkansas diamond deposits.

See ARKANSAS.

 
Orpin-Palmer Diamond out-of-round diamond oval cut PDF Print E-mail
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Sunday, 23 September 2007

Orpin-Palmer diamond. The first of several large South African alluvial Diamonds found (1902) on the Vaal River Estate, Cape Province. Valued at £ 100, it was said to have been a 117.5-carat dull-white diamond. Its present location is unknown.

Ortlepp diamond. An uncut tri­angular-shaped stone (made) re­ported to be smaller than a shirt but­ton, and believed by some to be the first diamond discovered in the Kim-berley diggings. It was found in July, 1869 by Mrs. Sarah Ortlepp while resti ng u nder a shade tree. The Ortlepp stayed with the family for six genera­tions and is now on permanent loan to the Africana Museum in Johan­nesburg.

Otto Borgstrom diamond. A

121.50-carat, well-formed, yellowish octahedron that was found in the Gong Gong diggings on the Vaal River, Cape Province, Republic of South Africa, in 1907. The present whereabouts of this stone is not known.

Otto's Kopje (kop"-e). A small dia­mond pipe mine in the Kimberley area, Cape Province, Republic of

South Africa. Unlike the roughly cir­cular shape of most volcanic pipes, it is a wide and irregular volcanic fis­sure.

Oubangui-Chari. Formerly a territory within French Equatorial Africa, now the Central African Republic. Sig­nificant diamond production comes from both East and West Oubangui.

See EAST OUBANGUI, WEST OUBANGUI.

out-of-round diamond. A term used to describe any brilliant or other style of round-cut diamond that does not have a truly circular girdle outline to

the eye; a stone with a girdle circum­ference that is appreciably oval or squared but not constituting a fancy shape. See symmetry

outside goods. diamond rough sold by the diamond Trading Co., Ltd., which has been purchased either from the diamond Producers' Association, Ltd., or from such other sources as Angola, Ghana or Sierra Leone. That purchased from other than a mem­ber of the Producers' Association is


lermed outside goods. Outside goods also refer to those sold "outside" of the diamond Trading Co., Ltd.

oval brilliant cut. See oval cut

oval cut. (1) A brilliant style of cut-ling in which the girdle outline is el­liptical; i.e., a rounded oblong. Also called the oval brilliant cut. (2) An obsolete barrel-shaped style of cut­ting with a circular cross section and covered with triangular facets.

 
Or-i-Noor Diamond press Catherine PDF Print E-mail
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Sunday, 23 September 2007

Or-i-Noor diamond. See dewey dia­mond.

Orloff diamond. The 189.62-carat Orloff is one of the largest and most historically outstanding Diamonds in the world and one of the chief trea­sures in the Russian diamond Fund in Moscow. It resembles half of a small egg, is rose cut on top, almost flat and faceted on the bottom, and measures % x 114 x 13/s inches. Stories of the Orloff's history differ. Many authorities and writers believe that it is the Great Mogul, which was seen in India by Tavernier, the French traveler and jeweler, but that has been lost to history since that time. If this is true, it was probably part of the 1739 Nadir Shah plunder that was taken during the pillage of Delhi. It is probable that it was stolen after Nadir's assassination and eventually found its way to Amsterdam by devi­ous ways, including theft and mur­der. According to another account, the great diamond was originally the eye of the Hindu god Sri-Ranga in a temple in Srirangem, District of Tri-chonopoly, about 100 miles from the southern tip of India. It was stol­en from the temple by a French sol­dier, who had deserted the army after fighting in the Carnatic Wars and who fled to Madras and sold the stone to a sea captain for $10,000. The captain, in turn, is said to have sold it in London for $60,000 to a Persian merchant named Khojeh, who took it to Amsterdam. It was there, in 1775, that the Russian nobleman, Count Gregory Orloff, bought the big egg-shaped gem for $450,000 and presented it to Em

press Catherine II, in an attempt to regain his place as her favorite. She accepted the gift, but refused to reinstate Orloff to his former power­ful position in the Court. Catherine never wore the Orloff, but had it mounted on top of the double eagle in the Imperial Sceptre, the form in which it exists today in the Kremlin Museum. The name is also some­times spelled Orlov or Orlow. Alter­nate names sometimes encountered are Amsterdam, Lasarev, Sceptre, or Scepter.

 
Orapa Pipe & Diamond Mine Orchid Diamond wholesaler O'Reilly Diamond PDF Print E-mail
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Sunday, 23 September 2007

Orapa Pipe & diamond Mine. Orapa pipe formerly designated 2125, second largest diamond pipe.

Orchid diamond. Described as hav­ing a "pink-lavender color," this 30.45-carat crystal was imported in 1935 by Lazare Kaplan & Sons, Inc., New York City diamond cutters, who fashioned it into a 9.93-carat em­erald cut. This rare-colored gem was exhibited in museums in Boston and Cleveland and was sold in 1940 to a private buyer through a


wholesaler. One overly poetic gen­tleman once described it as "contain­ing all the color of a mile of tropical sunset." In 1965 it was reported to have changed hands, but the present owner is unknown. Oregon diamond. A 3.87-carat, grayish-green distorted octahedron. Found in 1893 near Oregon, Dane Co., Wisconsin. Purchased by Tiffany & Co. for $50 and presented to American Museum of Natural His-


tory, New York City. It was stolen from the Museum and never recov­ered.

O'Reilly diamond. See eureka dia­mond.

O'Reilly, John. Came hunter and trader in the old British Cape Colony which is now known as the Republic of South Africa. Van Niekerk en­trusted a stone found by Erasmus Jacobs to O'Reilly in 1867 to have it examined at Colesberg. The stone proved to be a 21.25-carat diamond which made African Diamonds known to the world and initiated fur­ther development of the great dia­mond fields of South Africa. This was the first authenticated diamond find in South Africa. It was later cut to a 10.73-carat brilliant and named the Eureka diamond. See eureka diamond.

Oriental diamond. An obsolete term that was once used to distinguish In­dian from Brazilian Diamonds after the discovery of Brazilian deposits and while Indian stones were still a factor in the market.

original lot. An unsorted lot of rough Diamonds sold by the diamond Trad­ing Co. See lot.

 
optical density optical separator orange Orange River Oranjemund PDF Print E-mail
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Sunday, 23 September 2007

optical density. See optically dense, re-

I RACTIVE INDEX.

optical separator. A device devel­oped by the diamond Research Lab­oratory, Johannesburg, Republic of South Africa, for the recovery of Diamonds from worthless material. It is based on the difference between the light-reflecting properties of dia­monds and other gravel constituents.

See diamond RESEARCH LABORATORY.

orange

diamond. A diamond of a distinct orange tint. It does not refer to a diamond from the Orange River Valley, although most stones of this color are found in the Republic of South Africa. Many of them are red­dish orange-brown, somewhat simi­lar to the color of some zircons. Others are a more vivid reddish-orange color, reminiscent of flame spinel. Some vivid deep-orange dia­monds have been found in the Wes-selton Mine. Few of these Diamonds reach the North American trade. They are properly called fancies.

Orange Free State. A province in the Republic of South Africa, south of the Transvaal, that was formerly a vir­tually independent colony of Boers. Some important diamond mines, such as Jagersfontein and Koffiefon-tein, are located in the province. Al­luvial production from the Orange Free State has practically ceased, however.

Orange River. The principal river in the Republic of South Africa along


which, together with its main tribu­tary, the Vaal, are located many of the country's alluvial diamond depos­its. It forms the boundary between South-West Africa and the Republic of South Africa, and rises in Lesotho (formerly Basutoland). The first large white rough diamond, the 83.50 carat Star of South Africa or Dudley diamond, found in the Orange River, was fashioned into a 47.75-carat oval brilliant.

Orange Tiffany diamond. See tiffany

diamond.

Oranjemund. A town about five miles north of the mouth of the Or­ange River that is maintained by Consolidated diamond Mines of South-West Africa, Ltd., for its em­ployees. Important mining activity is carried out not far to the north. See

SOUTH-WEST AFRICA.

Orapa pipe. The world's second largest known kimberlite pipe, de­signated 2125 AK/1. It is part of the Letlhkane group of kimberlites, lo­cated in the area of Orapa on the eastern edge of the Kalahari desert, about 210 miles north of Gaborone, the capital of Botswana. The Orapa pipe was discovered by the De Beers prospecting team, in 1967, under the sands and gravels of the Kalahari desert. Officially opened on May 26, 1971, it came into production July 1, 1971. It is oval in plain view, 1.2 km. x 1.61 km., with a surface area of 113 hectares (280 acres), and re­ported to be about 5,000 feet deep. The preliminary assessments indicate a ratio of Gemstones to industrial Diamonds of 10 to 90, respectively. Ore reserves have been proven to 37 meters depth (about 120 feet) which

 
Oppenheimer, Harry Oppenheimer, Sir Phillip PDF Print E-mail
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Friday, 21 September 2007

Oppenheimer, Harry (1908- ).

Son of Sir Ernest Oppenheimer and successor, upon his father's death in 1957, to the chairmanship of De Beers Consolidated Mines, Ltd., Anglo-American Corporation, Ltd., and a number of other companies in the De Beers group. He has con­tinued this work with notable suc­cess, bringing into the De Beers fam­ily, in partnership with the Govern­ment of Tanzania, the Williamson diamond Mine and initiated the marketing of Russian Diamonds with Soviet authorities outside the Soviet bloc through the Central Selling Or­ganization. Greater stability has also been achieved for the diamond in­dustry in Sierra Leone. See op­penheimer, SIR ERNEST.

Oppenheimer, Sir Phillip (1911- ).

Nephew of the late Sir Ernest Op­penheimer. Managing director of the


Central Selling Organization in Lon­don and director of the Anglo-American Corporation and De Beers Consolidated Mines, Ltd.

Oppenheimer Student Collection. A

collection of more than 1500 carats of rough gem and industrial dia­monds that was presented to the Gemological Institute of America in


1955 by the diamond Corporation, Ltd., through the good offices of the late Sir Ernest Oppenheimer, Chair­man of the Board of the Corpora­tion, for educational and instruction­al purposes. optical density. See optically dense, re-

I RACTIVE INDEX.

 
Oppenheimer, Sir Ernest PDF Print E-mail
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Friday, 21 September 2007

Oppenheimer, Sir Ernest (1880-

1957). Sir Ernest Oppenheimer, who later became universally known as "the King of Diamonds," was born in Freiberg, Germany, in 1880. He started his illustrious career in the diamond industry in 1896, at the age of sixteen, when he joined the London diamond firm of Anton Dun-kelsbuhler & Co. as a sorter and grader. He soon gained a reputation for proficiency, and in 1902, at the age of twenty-two, Dunkelsbuhler's sent him to their office in Kimberley, South Africa, where they needed competent graders. In 1917, he joined an American consulting en­gineer for a gold-mining company


and organized the Anglo-American Corporation of South Africa, Ltd., which was a success from the start. The gold fields in which they held interests were so productive and profitable that Oppenheimer, who had become chairman of Anglo-American, began searching for further opportunities. Keenly aware of the potentialities of the diamond fields of South-West Africa, he bought up mines formerly owned by Germans after the war and amalga­mated them under Consolidated diamond Mines of South-West Af­rica, Ltd., in which Anglo-American held a controlling interest. This act made him an important figure in the diamond-producing world. Within a year, Consolidated Mines was ac­counting for one-fifth of all the dia­monds mined in Africa. In 1926, Sir Ernest was appointed a director of De Beers; later he became chairman. He had De Beers buy out Anglo-American's interest in Consolidated. Then, he set up a firm called the diamond Corporation, Ltd., through which almost all of the world's dia­monds were sold, and the prices regulated. In 1933, he organized a subsidiary firm called the diamond Trading Co., Ltd., to serve as the sole channel through which the diamond producers sold their stocks of gem Diamonds. At the time of his death, on November 25, 1957, Oppen­heimer was a director of 41 com­panies and the chairman of 28 others, including Anglo-American Corporation of South Africa, Ltd., De Beers Consolidated Mines, Ltd., Consolidated diamond Mines of South-West Africa, Ltd., the Dia­mond Corporation Ltd., and Premier

 
old-miner onza para diamantes CULET, BRILLIANT CUTopen setting PDF Print E-mail
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Friday, 21 September 2007

old-miner. An abbreviated form of old-mine cut diamond.

old single cut. A simple form of bril­liant cutting that has a octagonal-shaped girdle outline, a table, 8 bezel facets, 8 pavilion facets, and sometimes a culet. Used for small Diamonds.

Ombelle M'Poko. A minor dia­mond-mining area in the Central African Republic.

one-grainer. See grainer.

onza para diamantes. Spanish, meaning the diamond ounce. Equal to 431.42 English grains.

onzuiver. A Dutch word meaning impure. It is used by some diamond men to refer to an imperfect dia­mond.

open cast mining. Surface mining, in which the ore (diamond for exam­ple) is exposed to the sky by remov­ing the overburden. All pipe mines are first worked from the top down­ward by this systematized method. The Finsch Mine is an excellent ex­ample of the open cast method of mining.

open culet. A culet that is larger than necessary; usually, one that is visible to the unaided eye. It may be de­scribed as medium, large or very large. See culet, closed culet, off-center

CULET, BRILLIANT CUT (ROUND). (See photo.)

opening a diamond. In the dia­mond-cutting industry, a trade term used to describe the operation of polishing a facet, or "window," on the surface of a heavily coated or rough-surfaced diamond, so that a clear view of the interior can be had


by the cutter before proceeding with the work. A window must be ori­ented properly, so as to eliminate dis­tortion caused by refraction of light.

open setting. A stone setting in which the mounting holds a stone with the pavilion facets open to the light; effectively used with transpa­rent stones, especially diamond.

open table. A term that is sometimes used to refer to the table on a spread, or swindled, stone. To some, any table diameter of 60% or more of the girdle diameter is open; to others, open means 65% or more. See table;

TABLE SIZE; SPREAD STONE; SWINDLED STONE; PROPORTIONS, GOOD.

Oppenheimer diamond. In 1964, Dutoitspan, the famed mine near Kimberley, South Africa, was the site of discovery of a large, pale-yellow octahedron. The Oppenheimer has only a few small black inclusions and is transparent and unusually well formed. It measures about 1% x VA inches and weighs 253.70 carats. In the same year, the owner, Harry Winston, New York City gem mer­chant, donated the superb crystal to the Smithsonian Institution,


Washington, D.C., in memory of Sir Ernest Oppenheimer, late Chairman of the Board of De Beers Consoli­dated Mines, Ltd. In 1971, it was dis­played at the "De Beers Hall" of the mining museum in Kimberley, Re­public of South Africa. Alternate name: Dutoitspan diamond.

 
off-center table Offin River Estates oitava old-mine cut PDF Print E-mail
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Friday, 21 September 2007

off-center table. Distorted rough is sometimes cut in a manner that places the table nearer to the girdle at one point than elsewhere. It is the result of the opposite crown facets being cut at different angles. May also be off-center because opposing bezels are of different sizes. An off-center table may be inclined to the girdle plane, but usually it is parallel

tO it. See TABLE, TABLE SIZE, SYMMETRY.

off-color diamond. (1) In the Ameri­can trade, any diamond that has a tinge of undesirable color, especially yellowish or brownish, that is easily apparent to the unaided but prac­ticed eye without comparison with a stone of known color. (2) A term that has been used at the South African diamond mines for the grade of rough Diamonds below the cape and bye grades.

Offin River Estates, Ltd. A small diamond-mining company that works alluvial deposits in the Birim River Valley, Oda district, Ghana (Gold Coast). Production is not great. See ghana.

oilie. (1) In the American diamond trade, a little-used term that is synonymous with Premier diamond. (2) In some European countries, the term applies to a diamond having a blue-green tint. See premier diamond.

oil stones. A term used by South Af­rican miners for agates found asso-


ciated with Diamonds in the alluvial diamond deposits.

oitava (or octavo). A Brazilian weight for Diamonds and other gems; the equivalent of about \7Vi carats. Oktyabrksy diamond. One of the many large (weight unreported) named rough diamond crystals in the Russian diamond Fund at the Krem­lin.

old-English cut. Same as single cut. old-European cut. A term applied to the earliest form of circular-girdled full brilliant. It is characterized by a very small table, a heavy crown, and great overall depth. Improperly refer­red to as old-mine cut.

Old-European cut

Old-Mine cut


old-mine cut. (1) A trade term that is applied properly to an early form of brilliant cut with a nearly square or cushion-shaped girdle outline. (2) A term applied occasionally and incor­rectly to a somewhat more modern style of brilliant cut that also has a much higher crown and smaller table than the modern brilliant cut, but whose girdle outline is circular or approximately circular a style of cutting that is more properly call-

 
oblong cut octagon cut cubic, or isometric, crystal system PDF Print E-mail
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Friday, 21 September 2007

oblong cut. Same as emerald cut. Occidental diamond. A misnomer for rock crystal.

Ocean of Light diamond. See darya

l-NUR diamond.

octagon cut. An octagonal (eight-sided) form of cutting, usually step cut, the length and angles of the sides of which may vary.

octagon work. The operation of plac­ing the eight main facets on the crown and pavilion of a diamond, thus converting the table into an oc­tagon shape.

octahedral cleavage (ahk'-tah-he"-dral). Cleavage parallel to any of the four pairs of faces of the octahedron.

See OCTAHEDRON, CLEAVAGE, CLEAVAGE (IN diamond).

octahedron (ahk'-tah-he"-dron).

Octahedron


One of the seven basic (and the most common) forms in the highest sym­metry (hexoctahedral) class of the

cubic, or isometric, crystal system. It has eight equilateral, triangular faces, each of which intersects all three of the crystallographic axes at an equal distance from the center. See cubic

SYSTEM, HEXOCTAHEDRAL CLASS. (See

photos.)

octavo. Same as oitava.

Oda. The district in the Eastern Prov­ince of Ghana in which major dia­mond deposits are located. See

GHANA.

Oersonskraal. A minor alluvial dia­mond deposit in the Wolmaransstad area, Transvaal Province, Republic of South Africa. Approximately 700 carats were reported from this dig­ging during one recent year.

off-center culet. A culet that, due to differences in the angles of the op­posite pavilion facets, is off center with respect to the girdle outline. It usually results from repairing or re-


polishing a portion of the pavilion or from attempting to retain maximum weight from a distorted piece of rough. Off-center culets often result from pavilions at the same angles but of different sizes. See culet, closed

CULET, OPEN CULET, BRILLIANT CUT (ROUND).

 
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