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Eye of Brahma Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Eye of Brahma diamond. See black

ORLOFF DIAMOND.

Eye of Shiva Diamond. See nassak

DIAMOND.

"eye perfect." A term that implies that no internal flaws or surface


blemishes are visible to the eye of a qualified diamond-clarity grader. In practice, it seems to be used mostly to describe stones with imperfections that can be seen only with difficulty by the unaided eye. It is prohibited by the American Gem Society for use by its members. It is also prohibited by the Federal Trade Commission, unless the stone meets the Commis­sion's definition of the term perfect.

See PERFECT, FLAWLESS, EYE CLEAN.


 
external characteristic PDF Print E-mail
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Wednesday, 19 September 2007

external characteristic. (1) A general term used to refer to any external or surface imperfection. (2) An alternate term for blemish. See blemish, flaw, im­perfection.

extra color. A term used in classify­ing Diamonds at the source for the second finest color grade.

extra facets. Facets in excess of those needed to achieve the planned symmetry of a given style of cutting. They usually result from polishing away nicks, chips, naturals, abra­sions and other blemishes on or near the surface, or they may be a cutting error. Extra facets are considered as blemishes if on the crown or visi­ble through the crown. See cutting, facet, symmetry.

extra-fancy gem blue. A term applied by some diamond men to diamonds of fine color; however, it is often used for lower grades.

extrusive rock. See igneous rock.

"eye-clean." A term that implies that no internal flaws are visible to the unaided eye of a qualified dia­mond-clarity grader. It is prohibit­ed by the American Gem Society for

 
Excelsior Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Examolite (trademark, Macbeth Daylighting Corp.) A diamond lamp designed to provide the approximate equivalent of north daylight. It is used both for displaying and grading Diamonds for body color.

Excelsior Diamond. From 1893, when it was found, until 1905 and the discovery of the colossal Culli-nan, the Excelsior was the largest diamond known to man: It weighed 995.20 carats, or about seven ounces! The Jagersfontein Mine, where it was found, was far from the early river diggings in South africa; in fact, it was an open-pit mine, where the gems were found in a dry


clay miles from any river bed. The huge lump was discovered acciden­tally by a native, when he picked up a shovelful of gravel he was throwing into a truck. He concealed it from the overseer, until he had an oppor­tunity to deliver it directly to the mine manager. In addition to a cash settlement, he was given a fine horse, a saddle and a bridle. In shape, the stone was flat on one side and rose to a peak on the other, simi­lar to a loaf of rye bread. This may have suggested the name Excelsior, which means more lofty or ever higher. Its color was said to be a true blue-white, something exceedingly rare in a diamond. Probably, how­ever, it was a typical Jagersfontein product: colorless under incandes­cent light, but given a bluish cast by the ultraviolet in daylight because of strong fluorescence. The stone was not cut until 1903, when it was en­trusted to the skill of Henry Koe of Asscher's Diamond Co. in Amster­dam. The yield was six pear shapes weighing 69.80, 47.15, 47.03, 34.97, 18.00 and 16.81 carats; four mar-


quise cuts weighing 40.36, 28.55, 26.37 and 24.38 carats; and eleven brilliant cuts, having a combined weight of 20.33 carats. This was a total of 373.75 carats, representing a weight loss of 62Y2 percent. Tiffany & Co. handled some of these stones in its old store on Union Square in New York City, but the exact number and final disposition of each has never been made public. In 1939, one of the marquise cuts was shown by De Beers Consolidated Mines, Ltd., at the House of Jewels at the New York World's Fair
 
European cut PDF Print E-mail
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Wednesday, 19 September 2007

European cut. A term sometimes applied to a diamond brilliant whose proportions are based on light falling perpendicularly on the crown. It was never adopted as a common form of cutting. Angle of pavilion facets to girdle, 38°40'; of bezel facets, 41 %'. The table is 56% of the girdle diame-


ter, crown 19%, and pavilion 40%. Not to be confused with the old European cut.

evaluation. See quality, factors that de­termine.

 
Eugenie Blue Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Eugenie Blue diamond. Believed to have been owned by Empress Euge'nie, this 31-carat heart-shaped diamond now resides at the Smith­sonian Institution. It was purchased from Harry Winston by Mrs. Mer-riweather Post of New York, who subsequently donated it to the Smith­sonian.

Eugenie Diamond. See empress euge'nie diamond.

Eureka Diamond. The Eureka has the distinction of being the first major diamond found in South africa; its

name, therefore, is most appropriate. A small boy, Erasmus Jacobs, the son of a Boer widow, picked up some pretty stones in 1867 on the banks of the Orange River and carried them home to his sister, Louisa. She used them to play a game called "five stones." A neighboring farmer, Schalk van Niekerk, was attracted by one of the "pebbles" and asked the widow if she would sell it. He even­tually entrusted the 21.25-carat stone to a traveling trader, John O'Reilly, who showed it to Lorenzo Boyes, Civil Commissioner of the town of Colesburg. Later, he took it to Grahamstown, where Dr. W. G. Atherstone, a geologist, identified it as a diamond worth £500. Sir Philip Wodehouse, Governor of Cape Pro­vince, purchased the gem at this price. It was shown at the Paris Ex­position of 1867-68 and attracted at­tention to South Africa in general and to the Cape in particular. In its cut form (a 10.73-carat brilliant), the Eureka was owned for many years by an Englishman, Peter Locan. It is known as the O'Reilly Diamond in South Africa. This historically impor­tant stone was exhibited in 1959 at the Ageless Diamond Exhibition in London. De Beers Consolidated Mines purchased the stone and pre­sented it to the Parliament of South Africa in Capetown in 1966. See

O'REILLY DIAMOND.


Last Updated ( Wednesday, 19 September 2007 )
 
Enterprise Nationale de Recherche et Exploitation PDF Print E-mail
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Wednesday, 19 September 2007

Enterprise Nationale de Recherche et Exploitation. A government or­ganization set up in Guinea, in 1961, to handle all prospective mining and dealing, following that government's nationalization of its diamond- and gold-mining industries. See guinea.

epaulet (or epaulette). A modifica­tion of the pentagon cut, the shape of which is produced by varying the length and angles of the sides.


Epaulet (or epaulette) cut

Estrela de Minas Diamond. See star

OF MINAS DIAMOND.

Estrela de Minas or Estrela do Sul Diamond. See star of minas diamond. Estrela do Sul Diamond. See star of

THE SOUTH DIAMOND.


estrellada. A Brazilian term for the deposits in which Diamonds are found.

etch pits. A pattern of pitting on the face of a crystal indicating crystal structure. Etched diamonds show various surface features such as triangular shapes aligned with edges of the face of the crystal (the oppo­site of a trigon) on octahedron faces, boat-shaped on dodecahedron faces, and square outlines on cube faces. Sometimes called etch figures.

eternity ring. The diamond eternity ring is a circlet of small diamonds set in a precious metal. This class of ring has been used in Europe for hun­dreds of years. The circle is the tradi­tional symbol of eternity.

 
English double-cut brilliant PDF Print E-mail
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Wednesday, 19 September 2007

English double-cut brilliant. Same as English square-cut brilliant.

English Dresden diamond. A 119.50-carat diamond that was found in the Bagagem Mine, Minas Gerais, Brazil, in 1857. E. H. Dresden, a London merchant, purchased the stone, had it cut by Coster of Amsterdam into a 76.50-carat pear shape. Dresden later sold it, in 1864, to an English merchant in Bombay for $200,000. It was subsequently purchased by the Gaekwar of


Baroda, in whose family it remained until 1934. The English Dresden is now believed to be owned by Curset-jee Fardoonji of India. It was first called the Dresden Drop and later abbreviated to Dresden, the word English was added later, to distin­guish it from the Dresden Green and other historic Diamonds of the same name in the Crown Jewels of Saxony. It is sometimes called the Star of Dresden Diamond. See Dresden drop

DRESDEN.


English round-cut brilliant

English round-cut brilliant. A style of diamond cutting that was fashion­able in England in the mid-19th cen­tury. It was perhaps the first round-girdle form of cutting, resembling slightly a modern brilliant when viewed from directly above the ta-


ble. However, since as much weight was retained from octahedral rough as possible, the cut was very lumpy. The total depth approximated the girdle diameter.

English square-cut brilliant. Also, known as English double-cut bril­liant. An early style of cutting having 16 crown facets, 12 pavilion facets, an octagonal table, and a culet.

 
Engagement Rings, Diamond Rings, Diamond Engagement Rings buy PDF Print E-mail
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Wednesday, 19 September 2007

engagement ring. A ring given in token of betrothal, especially a diamond solitaire so given by a man to his fiancee.

g. A ring given in token of betrothal, especially a diamond solitaire so given by a man to his fiancee.

 
Emperor-lite PDF Print E-mail
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Wednesday, 19 September 2007

Emperor-lite. A trademarked name for colorless synthetic corundum. Emperor Maximilian diamond. June 19, 1867, is a date that will be long remembered in Mexican history. On that day, the ill-fated Emperor of Mexico, Ferdinand Maximilian Joseph, was shot to death at Quere-taro with his generals, Miguel Mira-mon and Tomas Mejia. Around his neck at the time of the execution was a little bag containing a diamond that has come to be known as the Em­peror Maximilian. It is a 42-carat stone with an odd. violet fluores­cence in daylight. After his death, it was sent to Empress Carlotta, who was then in Europe trying to obtain help for her husband. Later, it was sold to help pay expenses during her mental illness. The Emperor Maximi­lian was exhibited at the Century of Progress Exposition in Chicago in 1933-34 by its then owner, Ferdinand Hotz, a Chicago diamond dealer. After his death, it was sold to a pri­vate collector in New York City, whose name has not been divulged.

See MAXIMILIAN DIAMOND.

Empress Eugenie Diamond. De­scribed as a perfectly cut, oval-shaped 51-carat brilliant of possible Brazilian origin, the Eugenie first came to public attention after Em­press Catherine II (Catherine the Great) ascended the Russian Throne in 1762, when she wore it as the center stone in a hair ornament. About 1787, the Empress presented it to her favorite, Prince Grigori Potemkin, in recognition for his ser­vices, both diplomatic and military, and for conducting her triumphant


tour through the newly acquired Crimea. She further bestowed on him the surname Taurisschesky (from the name for Crimea, Khersonesus Taurica) and a magnificent palace called the Tauria. Potemkin died in 1791, after which his extensive col­lection of jewelry was inherited by his favorite niece, Countess Branitsky, who later willed the stone (then known as the Potemkin Diamond) to her daughter. From this grandniece of Potemkin, Emperor Napoleon III of France purchased the diamond in 1853 as a wedding gift for his bride, Eugenie de Montijo. Now, mounted in a handsome necklace, Euge'nie gave it her own name, by which it is still known to­day. After the Franco-German War and the fall of the French Empire in 1870, the Empress escaped to Eng­land with some of her jewels, includ­ing her beloved diamond, and placed them in safekeeping with the Bank of England. Although many of these jewels were sold at Christie's, the renowned London auction house, ownership of the Eugenie is said to have been transferred to Mulhar Rao, the Gaekwar of Baroda, for approximately $75,000. Besides being one of the wealthiest men in the world and an avid gem collector, this Maharatta prince became

notorious for his reported attempt to murder the British resident, Colonel Phayre, by mixing diamond powder in his food. This was in 1874. But the plot was unsuccessful and he was tried on a charge of poisoning by a jury of three Englishmen and three Indians. The result of the trial was a failure to obtain a unanimous ver­dict. However, the Viceroy, Lord Northbrook, decided to depose the Gaekwar merely on the grounds of misgovernment! After this incident, the Eugenie disappeared, together with many other large Diamonds, in­cluding the Star of the South and the English Dresden. Later (exact date unknown), the Eugenie reappeared and came into the possession of Mrs. N. J. Dady of Bombay. Since her death a number of years ago, how­ever, there has been no clue to the present whereabouts of this histori­cally important diamond. All efforts by the Gemological Institute of America to locate the stone and es­tablish ownership have proved fruit­less.

Last Updated ( Wednesday, 19 September 2007 )
 
emission spectrum PDF Print E-mail
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Wednesday, 19 September 2007

emission spectrum. The spectrum of the radiation produced by a given source. If a diamond is heated to a



Emerald cut

white heat, an emission spectrum will be produced that is characteris­tic of carbon and the impurities within the stone. A second type of emission spectrum results from fluorescence; i.e., a secondary radia­tion caused by excitation by X-rays, ultraviolet rays, cathode "rays or visi­ble radiation. Emission spectra may be continuous or seen as a series of bright lines in the spectroscope. See

ABSORPTION SPECTRUM, FLUORESCENCE, SPEC­TROPHOTOMETER, SPECTROSCOPE, SPECTRUM.

Emperor Justinian Diamond. The

story surrounding this 25-carat dia­mond is legendary. It is said to have slipped out of the Crown of the Em­peror Justinian during his trium­phal procession in Constantinople in the year 548 A.D. The mishap is supposed to have occurred in the "Place of the Hebdomen," a public square. The stone was not found. It is said that centuries later a child, play­ing in the soil of that same square,

 
. emerald cut PDF Print E-mail
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Wednesday, 19 September 2007
. emerald cut. A form of step cutting. It usually is rectangular but some­times is square, in which case it is known as a square emerald cut. It has rows (steps) of elongated facets on the crown and pavilion, parallel to the girdle, and with corner facets. The number of rows, or steps, may vary, although the usual number is three on the crown and three on the pavilion. The emerald cut is seldom used for Diamonds in the inter­mediate color grades, since it tends to emphasize color. It is excellent, however, for colorless stones and when it is desirable to emphasize the color of fancy colors. See step cutting.
 
El Pao PDF Print E-mail
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Wednesday, 19 September 2007

El Pao. One of the principal alluvial diamond deposits in the Upper Ca-roni field, Venezuela. See Venezuela.

eluvial deposits. (1) Represent in

coherent concentrations of heavier, resistant minerals (e.g. Diamonds, gold, platinum) weathered from ma­terials in place or transported short distances downslope from weathered sources that crop out on hill slopes above them. They may, in part, be considered as intermediate between true depositional (alluvial) placers and true residual deposits. (2) Some­times formed by weathering and concentration in place by the action of wind or rain wash

 
Elizabeth PDF Print E-mail
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Wednesday, 19 September 2007

Elizabeth. A minor alluvial diamond deposit in the Lichtenburg area, Transvaal Province, Republic of South africa. The annual yield from this mine is inconsequential.

Elizabeth Bay. An area of alluvial-diamond deposits in South-West Af­rica. It is virtually exhausted and is no longer being worked.

Elizabeth Pink Diamond. See William­son DIAMOND
 
electrical conductivity PDF Print E-mail
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Wednesday, 19 September 2007

electrical conductivity (of diamond).

The electrical resistance of diamond is very high; therefore, it is essen­tially a nonconductor. Pure, color­less, single crystals of diamond have a higher resistance than impure va­rieties such as bort. Type lib dia­mond, a rarely encountered form, is a semi-conductor. Diamonds with a natural blue color are all Type lib, whereas those to which a blue color has been imparted by electron bom­bardment are nonconductors. Thus, this kind of artificial coloration can be detected with a conductometer.

See CONDUCTION DETECTOR (AUDIO), CON­DUCTOMETER, ELECTRON-BOMBARDED DIA­MOND, TYPE II DIAMOND.

electron-bombarded diamond. A

diamond whose color has been changed to blue by bombardment with fast electrons in a Van de Craaff Generator. Such a stone can be de­tected readily by a conductometer, since treated blue stones are non­conductors of electricity and natu­ral blue stones are conductors. Gamma-ray radiation also has been used to produce blue colors. See

CONDUCTOMETER, CONDUCTION DETECTOR (AUDIO), ELECTRICAL CONDUCTIVITY (OF DIA­MOND), TYPE II DIAMOND, VAN DE GRAAFF GENER­ATOR.

electrostatic separation process. A

method of recovering tiny diamonds from mill concentrates that makes use of the fact that almost all dia­monds are very poor conductors of electricity, compared with the as­sociated minerals in the concentrate. The apparatus consists essentially of


a grounded electrode and a charged electrode placed opposite one another and fairly close together. A high-tension field is maintained between the two electrodes, the charged electrode being of positive polarity. When the concentrates are passed through the high-tension field, all particles obtain an induced charge. The associated minerals, being relatively good conductors, allow their charge to leak away to the ground as they pass over the grounded electrode of the separator. In this manner they acquire negative potential and are therefore attracted towards the positive high-tension electrode. The induced charge on the surface of the nonconductive diamonds cannot leak away quickly enough; they retain their positive charge, and are therefore repelled from the high-tension electrode. A separation is thus achieved. The method is much less expensive and time consuming than hand sorting and permits the recovery of small al­luvial stones and those from weath­ered kimberlite, neither of which will adhere to the conventional grease table. See x-ray separator.

 
eight cut PDF Print E-mail
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Wednesday, 19 September 2007

eight cut. Also called the single cut. Extremely simplified form of the bril­liant cut used for small Diamonds usually below about 2 mm. diame­ter. Usually has 17 facets (no culet); 8 facets surround the table and 8 facets form the pavilion. See single cut.

eighth. A common abbreviation for an eighth carat.

eight-square stone. See blocker Eisenhower diamond. The "Crater of Diamonds," a kimberlite pipe near Murfreesboro, Arkansas, yielded this 3.11-carat diamond in 1957. The name was chosen by the Dallas, Texas, Gem & Mineral Society, be­cause it resembled the profile of the then President Eisenhower in carica­ture. In 1958, it was mounted, still uncut, as a pendant with a platinum chain by its discoverer and owner Mrs. Ruth McRae of Irving, Texas, now Mrs. Ruth Larson of Dallas.

E.K.L. Consortium. See societe's de

L'E.K.L.

Elandsfontein. See jonker diamond. Elandsputte. An alluvial digging situated near Lichtenburg, Transvaal, Republic of South africa. It was the scene of a famous diamond rush in


1926 when 6,000 (the number has been put as high as 10,000) diggers took part in the race to stake claims. The deposit is almost worked out to­day. See lichtenburg.

 
economy stone Edna Star Diamond PDF Print E-mail
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Wednesday, 19 September 2007

economy stone. A term that is used infrequently for a diamond of about crystal color or lower and slightly imperfect to imperfect.

edge up. A diamond positioned so that it is being observed parallel to the girdle plane, a position com­monly used for detecting faint tints of color. See face up well.

Edna Star Diamond. A 115.0-carat emerald-cut diamond, purchased by Harry Winston, the New York City gem merchant, in 1956. It is set in an elaborate clip-pendant combination and was sold by Harry Winston in the Middle-East in 1957. Its previous history is unknown.

Eerstebegin. A minor alluvial diamond deposit in the Schweizer Reneke area, Transvaal Province,

 
Earth Star Diamond PDF Print E-mail
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Tuesday, 18 September 2007

Earth Star diamond. This 111.59-carat coffee-brown pear-shaped dia­mond was cut from a 248.90-carat rough found in the Jagersfontein Mine, South africa, in 1967. It is


thought to be the largest brown dia­mond in the world and was exhi­bited along with many other notable Diamonds in the "De Beers Hall" of the mining museum in 1971.

East Oubangui. A diamond-producing region within the Central African Republic. Total annual pro­duction in recent years has been be­tween 30,000 and 50,000 carats. The producing companies are Societe Miniere du Intercoloniale (SMI), Societe Miniere du Zamza, and Societe Miniere de I'Est Ouban­gui (SMEO).

Ebenhauzer Mine. A minor diamond pipe mine in the Koffiefontein area, Orange Free State, Republic of South Africa.

eclogite (ek"-low-jite). A pyroxene-garnet rock that is sometimes found in the South African diamond pipes. It is possible that diamond crystal­lized originally in eclogite.

 
Eagle (or Waukesha) Diamond PDF Print E-mail
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Tuesday, 18 September 2007

Eagle (or Waukesha) diamond. This 15.37-carat light-yellow diamond, a rounded dodecahedral crystal, was found in 1867 on a farm near Eagle, Waukesha Co., Wisconsin. The dis­covery was made in hard yellowish earth, at a depth of about 40 feet, during a well-digging operation. The farmer's wife who sold the stone seven years later to a Milwaukee jeweler for one dollar, thinking it was topaz, sued him when Tiffany's found it was a diamond, for which they had paid the jeweler $850. The crystal was then sold to J. P. Morgan, who later donated it, still uncut, to the permanent collection of the American Museum of Natural His­tory, New York City. In 1964, it was stolen from the Museum, together with other valuable gems and has not yet been recovered.

 
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