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nuclear reactor Nur-ud-Deen Nur-ul-Ain Diamond PDF Print E-mail
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Friday, 21 September 2007

nuclear reactor. A device by which a fission chain reaction can be in­itiated, maintained, and controlled. Its essential component is a core of fissionable fuel which usually has a moderator, a reflector, shielding, and a control mechanism. The nuclear radiation may take the form of gamma rays, or other nuclear parti­cles like alpha rays (helium nuclei), or beta rays (electrons). Neutrons, positrons, and protons also may be emitted along with the transmuta­tions. It is used to artificially color Diamonds. See cyclotron-treated dia­mond, PILE-TREATED diamond, TREATED DIA­MOND.

Nur-ud-Deen (Light of Faith) Dia­mond. A large (size unknown) pink diamond, mounted in the center of a cross, that belonged to Prince Alex­ander Tzary in the 19th century. The cross, which was embellished with 85 brilliants and 160 rose cuts, was sold in London, in 1898, for £750. No additional information is avail­able. Alternate spellings are Noor-un-Deen and Noor-ud-Deen.

Nur-ul-Ain diamond. A 60-carat pink diamond. Set in a diadem with 323 smaller Diamonds. Name means Light of the Eye. Belongs to Iranian Crown Jewels. Believed to have been cut from the Great Table. See darya-i-nur. Alternate spelling is Noor-ol-Ayn.

nyf. See naif.

Noor-ol-Ayn Diamond normal class North Star Diamond PDF Print E-mail
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Friday, 21 September 2007

Noor-ol-Ayn diamond. See nur-ul-deen diamond.

Noor-un-Deen diamond. See nur

UD-DEEN diamond.

normal. In the study of light, the NORMAL is an imaginary line drawn perpendicular to the surface of an optically dense medium. The NOR­MAL may be drawn through any given point on any surface to de­scribe the behavior of light at that

point. See diagrams, ancle of refrac-


normal class. See hexoctahedral class.

"north light." The traditional light source used in color grading dia­monds. North skylight or "north light" is illumination from the north­ern sky between 10 a.m. and 12 noon on a moderately overcast morning during the spring or fall. Custom has it that light reflected from the north sky affords the least variation of intensity and color, is relatively shadow free, and contains Ihe least amount of ultraviolet. How­ever, north skylight is not sufficiently c onstant from day to day, at different limes of the day, or from one locality to another to be entirely satisfactory as a light source standard. Also, be­cause of the presence of ultraviolet in sunlight, the color of stones that fluoresce blue improves in daylight. Consequently, GIA has developed a lighting system that closely approxi­mates the desirable qualities of north skylight for diamond color grading. The closest approximation for a true color balanced daylight, as used in Ihe GIA system, has a correlated color temperature of 6200° Kelvin. See diamondlux, diamondlite.

North Star diamond. A fancy 32.41-carat blue pear-shape cut from a 97-carat rough found in the Ja-gersfontein Mine. Baumgold Broth­ers bought, cut and polished the rough valued at $300,000 in 1969. No other information is available.

Nova Estrela do Sul (New Star of the South) diamond. A 140-carat

greenish diamond that was found in 1937 in the Abaete River, Minas Gerais, Brazil. The present location of this stone is unknown.

Nier-Gem Niekerk, Schalk van. See eureka dia­mond PDF Print E-mail
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Friday, 21 September 2007

Niekerk, Schalk van. See eureka dia­mond, STAR OF SOUTH AFRICA diamond.

Niekerk's Hope. One of the early al­luvial diamond diggings on the Vaal River, Cape Province, Republic of South Africa.

Nier-Gem. Trade name for man-made yttrium aluminum garnet (YAG).

nitrogen. Nonmetallic, colorless element symbol N, and a diatomic

gas (N2). Occurs as a trace element inclusion in the lattice in some dia­monds. Nitrogen occurs as aggregate in Type la or as dispersed-atoms in Type lb Diamonds. Nitrogen does not occur in Type II Diamonds. The pres­ence of nitrogen atoms dispersed through the crystal lattice in the order of one part in a million is be­lieved to cause the diamond to ab­sorb light in the blue region which

results in the yellowish-body color of Type I Diamonds. See type i diamond. Nizam (or Nizzam) diamond. An apparently unauthenticated stone thought to be in the treasury of the Nizam of Hyderabad (ancient Gol-conda) since before the Golconda diamond fields were exhausted. Some gem historians believe that it was found in Golconda's Kollur Mines about 1835. It was reported to have weighed either 440 or 340 carats in the rough and to have been broken during the Indian Mutiny in 1857. The Nizam may have been sold to an Indian banker for 70,000 rupees; at that time its value was placed at £ 200,000. After cutting, it was thought to have weighed 277 carats. Models made of it represent a concave-based, elongated, domed

stone covered with irregular, con­cave facets. Presumably, this great diamond has been owned by succes­sive generations of Hyderabad's rul­ers and retains this status today, al­though no confirmation has been made of this conjecture. The name is also sometimes spelled Nizzam.

Nizzam diamond. Same as Nizam diamond.

NMDC. See national mineral develop­ment CORPORATION.

Nooitgedacht. An alluvial diamond deposit near Barkly West, Cape Prov­ince, Republic of South Africa. Al­though owned by De Beers Consoli­dated Mines, Ltd., it is worked by private diggers. Recent annual pro­duction has been approximately 2000 carats.

Nooitgedacht diamond. The Noo­itgedacht yellow diamond rough weighing 325 carats was discovered by a native in the diggings at Noo­itgedacht, near Kimberley, Cape Province, Republic of South Africa, in 1953. The site had been dug for 22 years without success by its owner, Christoffel Boer. The diamond was sold by Boer for $38,000, and the discoverer was awarded $840. The disposition of the Nooitgedacht is not known.

Nepal Pink Diamond Nevada diamond New South Wale PDF Print E-mail
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Friday, 21 September 2007
Nepal Pink diamond. A stone re¬ported by a United States gem dealer, while in Nepal in 1959, as a 72-carat, old Indian cut, with a "soft, rose-pink" color. Further information lacking.
Netherlands Diamant-Speurwerk Centrum. A Dutch research center established in 1954 by the Amster¬dam Jewelers' Association for the purpose of carrying out investiga¬tions aimed at improving diamond cutting techniques and machines, and increasing the quality of the Netherlands product. Nevada black diamond. A misnomer for obsidian.
Nevada diamond. A misnomer for ar¬tificially decolorized obsidian.
New Eland Mine. A small diamond pipe mine in the Boshof area, Or¬ange Free State, Republic of South Africa.
New Jagersfontein Mining & Explo¬ration Co., Ltd. The company that owned the Jagersfontein Mine, in the district of Fauresmith, Orange Free State, Republic of South Africa. The mine was closed in 1971. The prop-

erty and plant were leased under an agreement to De Beers Consolidated Mines, Ltd. See JAGERSFONTEIN MINE.
New South Wales. The principal diamond-producing State in Aus¬tralia. See AUSTRALIA.
New Star of the South diamond. See
New Thor Mine. A small diamond pipe mine in the Winburg area, Orange Free State, Republic of South Africa.
New Union Coldfields Group. A South African mining concern, of which Star Diamonds (Proprietary), Ltd., in the Orange Free State, is a subsidiary. See STAR Diamonds (PROPRIE¬TARY), LTD.
Ngelehun. The site of a rich alluvial diamond deposit that was reported in 1958 in Sierra Leone.
N'Gounie. An alluvial diamond de¬posit in Gabon that has been all but exhausted.
Niarchos diamond. A 426.50-carat flawless diamond of exceptionally fine color that was found in the Pre¬mier Mine, Republic of South Africa, in 1954. The late Sir Ernest Op-penheimer (Chairman of De Beers Consolidated Mines, Ltd., the owner of the Premier Mine), who had the rough in his personal collection for a short time, valued it at $300,000. In
1956, it was sold as part of an
$8,400,000 parcel to Harry Winston,
New York City gem dealer, who, in
1957, cut it into a 128.25-carat pear-
shaped brilliant with 58 facets on the
crown and pavilion and 86 addi¬
tional facets around the girdle. In the
same year, it was bought by Stavros
S. Niarchos, Greek ship-builder

and industrialist, for a reputed $2,000,000. A 30-carat marquise and a 40-carat emerald cut were also ob¬tained from the same rough. It was pictured in color in the April 1958 issue of National Geographic Magazine. Also known as the Ice Queen and the Pretoria diamond. nick. A minor chip out of the surface of a diamond, usually caused by a light blow. Nicks are more likely to be found along the girdle than elsewhere, although they may also appear along a facet junction or on a facet.
National Diamond Mining . natural point negative crystal Nepal Diamond PDF Print E-mail
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Friday, 21 September 2007

National diamond Mining Company (Sierra Leone) Ltd. See diminco. National Mineral Development Company (NMDC). A government agency in charge of exploration and development of mineral resources in India.

natural. A trade term for a portion of the original surface of a rough dia­mond that is sometimes left by the cutter on a fashioned stone, usually on the girdle. Naturals indicate an ef­fort to retain some extra weight from the original rough in the rounding-up and polishing operations. Some con­sider all naturals to be blemishes, whereas others contend that those that do not flatten the girdle outline nor extend beyond the width of a medium girdle should not be re­garded as blemishes. (See photo.)

natural grit. A term used to refer to diamond powder made by crushing natural Diamonds, as opposed to that consisting of man-made Diamonds,

called synthetic grit

. natural point. See point naif.

navet (nav-et"). A little-used English contraction of navette

. navette (nav-et"). From the French, meaning little boat. Navette and boat shaped are terms preferred in the colored-stone trade; marquise in the diamond trade. See marquise

Navsari. Indian diamond center.

Nawanger diamond. The 148-carat brilliant-cut Nawanger diamond was owned in 1970 by the Maharanee Gulabkumberba of Nawanger. It is reported to have come from Russia.

negative crystal. An angular cavity within a crystal or fashioned gem-stone, the outline of which coin­cides with a possible crystal form of the mineral in which it occurs. It is a rare occurrence in diamond.

Nepal diamond. Little is known about the beautiful 79.41-carat Nepal diamond, except that it is thought to have been mined in In­dia's Golconda region and that it was in the possession of Maharajah Bir Shumsher Jung Bahadur Rana of Nepal in the late nineteenth century. In 1901, it passed to his elder son,

Gehendra Shumsher, and it re­mained in the hands of Nepalese roy­alty until recent years. The stone has been described as striking and lovely in every respect colorless, flawless and well cut and polished. Mounted in an elaborate clip-brooch and pic­tured in the April, 1958 issue of Na­tional Geographic Magazine, it was then owned by Harry Winston, New York City gem dealer, who valued it at $500,000. It was shown at Lon­don's Ageless diamond Exhibition in 1959 and subsequently sold in 1961 to a private collector.

narrow cross section Nassak Diamond PDF Print E-mail
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Friday, 21 September 2007

narrow cross section. The maximum measured dimension through the smallest or narrowest diameter of the girdle outline in a fancy cut dia­mond. It is used in determining the depth and table percentages in pro­portion analysis. See fancy cut.

Nassak diamond. As first known in India, the Nassak was a 90-carat triangular-shaped stone; at present it is a magnificent, colorless, 43.38-carat emerald cut. This world-re­nowned diamond was once among the treasures of a Hindu temple near the city of Nassak, where it is said to have been the eye of an idol of the god Siva, deity of destruction and re­production. After the Maharatta War of 1818, it fell into the hands of the Marquis of Hastings and became part of the "Deccan Booty." The great diamond then became known as the Nassak. It was sent to England and was valued at $150,000, but in 1831 it was sold at auction during a seri­ous depression at the "distress" price of $36,000. In 1837, it again went to the auction block and was sold to the 1st Marquis of Westminster, who mounted it in the hilt of his dress sword. The stone remained in the Westminster family for almost a cen-

tury. Then, it was sold by the 2nd Duke of Westminster to Georges Mauboussin, the Paris jeweler, who brought it to America in 1926 for display as an artistic antique. By this time, it had been cut from its original Indian weight to an 80.59-carat stone of unusual beauty, still retain­ing its triangular shape. The diamond was then returned to Paris, where it was purchased by Harry Winston, New York City gem dealer. Winston brought it back to New York, re­fashioned it to its present 43.38-carat emerald shape, and sold it to the New York jewelry firm of Trabert & Hoeffer. Although brilliancy is les­sened somewhat by an unorthodox but attractive facet arrangement on the pavilion, the stone qualifies as one of the most impressive of the world's well-known Diamonds. In addition to being flawless and abso­lutely colorless, the polish is superb and the facet symmetry is above re­proach. In 1944, the Nassak was purchased by Mrs. William B. Leeds of New York City, who wore it in a ring with two tapered diamond ba­guettes. In 1970, it was auctioned at Parke-Bernet Galleries, New York, to Mr. Edward Hand for $500,000. Another name for the diamond is the Eye of Siva. Alternate spellings some­times used are Nasik, Nassac, Nas-sack and Nessuck. National Association of Goldsmiths of Great Britain and Ireland. Ab­breviation: NAG. Founded in 1894 exclusively for retail jewelers, it is the parent of the Gemmological As­sociation of Great Britain. A wide range of services is offered to mem­bers from inquiry and assistance to correspondence courses. The official

journal is the Watchmaker, jeweller and Silversmith. A Code of Trading issued by the NAG has established rules regarding diamond nomencla­ture.

naat Nadir Shah Namaqualand PDF Print E-mail
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Friday, 21 September 2007

naat. A Dutch term for a thin, flat, twinned diamond crystal; also the junction where the two crystals join. Cross naat is a nonparallel multiple twinning.

Nadir Shah. The leader of the Per­sians who, in 1739, invaded and sacked Delhi and carried off the famous Peacock Throne, together with several famous Diamonds. See


N.A.G. National Association of Goldsmith's, London. naif (pronounced "knife")- Also spelled naife, naive or nyf. A word of French derivation meaning the natural, unpolished faces of a dia­mond crystal; its luster or "skin." Other meanings, less frequently used, are as follows: (1) A well-formed diamond crystal, as distin­guished from a distorted one. (2) A thick or pointed diamond crystal, as distinguished from a flat one. (3) A diamond crystal possessing bright, or splendent, faces. See point naif. naife. See naif. naive. See naif.

Namaqualand (nah-mah"-kwa-land). A diamond-producing region located on Africa's southwestern coast. It is divided into two portions by the lower course of the Orange River: Little Namaqualand to the south (which forms a part of the Cape Prov­ince in the Republic of South Africa) and Greater Namaqualand to the north (which is the southern part of South-West Africa). The deposits are mostly in uplifted marine terraces, to the Diamonds were probably carried by long-shore currents from the mouth of the Orange. In the southern portion of Namaqualand the rich marine terraces are known as the oyster line, because of their content of oyster shells. Annual production, which is principally gem quality, reached 777,967 carats in 1974. The principal producing com¬panies are the Namaqualand State Mines and the Kleinzie Mine, both of which are controlled by De Beers, Consolidated Mines, Ltd.; the latter, however, has ceased production. Al¬ternate spelling Namakwaland. See NAMAQUALAND STATE MINES.
southwestern Africa. See NAMAQUA¬LAND
southwestern Africa. See namaqualand.
Napoleon diamond. A 34-carat bril¬liant, supposedly sold to Napoleon Bonaparte for £.8000, to be worn on
Namaqualand diamond producing areas
Namaqualand State Mines. The
government-operated alluvial dia¬mond mines in Namaqualand,

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