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Lobaye Loffa River LIBERIA. PDF Print E-mail
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Friday, 21 September 2007

Lobaye. A minor diamond-mining area in the Central African Republic.

Loffa River. The site of the discovery of an alluvial diamond deposit in 1955 in Liberia, West Africa. See

LIBERIA.

L'office Forestiere et Miniere du Congo. (FORMINIERE). One of the

principal diamond-mining com­panies in the former Congo Repub­lic, now in the Republic of Zaire. Recent production has been approx­imately 400,000 carats annually. See

REPUBLIC OF ZAIRE.

London. The name of a minor al­luvial diamond deposit in the Schweizer Reneke area, Transvaal Province, Republic of South Africa. The yearly production from this de­posit is insignificant.

long hexagon cut. A modification of the hexagon cut, the shape of which is produced by increasing the length


Long hexagon cut

of one of the three pairs of sides. It resembles a baguette with two pointed ends.

Longlands. A minor alluvial diamond deposit in the Barkly West area, Cape Province, Republic of South Af­rica. The total production in one re­cent year was 326 carats.

lonsdaleite. A hexagonal allotrope (polymorph) of diamond which has been found in meteorites and syn­thesized from graphite in the labora­tory by shock conversion. It is clas­sified as a Type III diamond.

loopkring. A Dutch word that refers to the inner section of the polishing lap, or scaife. It is on this part of the lap that the facets of a diamond are cut, or placed. Polishing and the removal of cutting marks is ac­complished on the outer section of the wheel, called the zoetkring. See

LAP.

loose goods. Polished but un­mounted Diamonds. See goods.

lot. (1) A group of rough Diamonds offered for sale by the diamond Trad­ing Co. to firms invited to view its sights. A lot usually includes a wide variety of material. (See sights.) (2) Also applied by diamond merchants to their regroupings of these dia­monds according to color, make, and


comparative freedom from imperfec­tions after fashioning. (3) Lots can also be composed of polished stones.

 
Litkie Diamond NAMAQUALAND Little Sancy Diamond PDF Print E-mail
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Friday, 21 September 2007

Litkie diamond. Found on the Vaal River, Cape Province, Republic of South Africa, 1891. 205 carats. Loca­tion unknown.

Little (or Lesser) Namaqualand. See

NAMAQUALAND.

Little Sancy diamond. Although from the collection of the same Seig­neur de Sancy of the French Court, this 34-carat pear-shaped brilliant cut should not be confused with the 55-carat Sancy diamond. The Little Sancy was bought by Prince Fre­derick of Orange in 1647 and passed down to his grandson, who became King Frederick I of Prussia. The gem was then in the Prussian Treasury for many years. It was worn on the Crown Necklace by the bride, Prin-


cess Mary of Sachen-Altenburg, at her wedding to Prince Albert of Prus­sia in Berlin in 1881. In 1923, it was inventoried among the Crown Jewels of the Hohenzollern as a pendant in a 23-diamond necklace. Today, still mounted as a pendant but of a much simpler design, the Little Sancy is one of the prize possessions of the Royal Prussian House in Bremen, Germany. An alternate name is the Beau Sancy.

load. A term used in the South Afri­can diamond mines for 16 cubic feet of blue ground, or about 4/5 of a short ton. Despite the fact that mine cars carry about 20 cubic feet, the standard load used for reporting yield is the 16-cubic-foot size.

 
light off-color light yellow COLOR-GRADING SYSTEM Dictionary PDF Print E-mail
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Friday, 21 September 2007

light off-color. A color-grading term used at the mines for a color better than off-color but inferior to second bye.

light yellow. A trade term used by some dealers to cover a wide range of colors in the low end of the dia­mond color-grading scale. Stones in this broad classification show a very obvious yellow tint to the unaided eye. For an approximate comparison of this grade to those used in the color-grading system of the Gem­ological Institute of America and the American Gem Society, refer to chart in Appendix entitled, Com­parison of Different diamond Color-Grading Systems. See also cia

COLOR-GRADING SYSTEM, ACS COLOR-GRADING SYSTEM, COLOR GRADE, CAPE, CAPE STONE, VERY LIGHT YELLOW, yellow diamond, SLIGHTLY YELLOW.

limonite. One of the alteration min­erals found in the kimberlite of the South African diamond mines. A yellowish-brown hydrous oxide of iron.

limpid (or limpidity). A diamond is said to be limpid if it is without body color and very transparent.

Linde Simulated Diamonds. Trade name for man-made yttrium alumi­num garnet (YAG)

1. Linobate. Trade name for man-made lithium niobate. See lithium niobate. Lisa Blue diamond. Originally de­scribed as a soft sky-blue-colored brilliant weighing 37.21 carats. At one time it was believed set in one of the crowns of the Emperor Char­lemagne. It was later recut to 37.05


Dictionary

carats and reported to be flawless and of a rare fancy blue color. This diamond set in a clip was sold in 1961 by Harry Winston in Canada. In 1967 he repurchased the diamond and subsequently resold it in Europe. Lisbon cut. A rarely used modifica­tion of the old-mine cut with an ad­ditional 16 facets.

Lisbon cut

lithium niobate. Relatively rare col­orless to colored man-made dia­mond simulant. Its hardness is about 6, S.G. = 4.64, R.I. = 2.21-2.30, and has a high dispersion of 0.120 for the Fraunhofer B-G lines. Manufactured by the Czochralski pulling method

 
Liberia Lichtenburg light brown light-field illumination PDF Print E-mail
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Friday, 21 September 2007

Liberia. A diamond-mining country on the southwest (Guinea) coast of Africa. The first discovery was made in 1910 in alluvial sands along the Joblong and Boa Rivers, about 30 miles inland from the capital, Mon­rovia. In 1955, new alluvial finds were made along the Loffa River, Suehn-Bopolu district, Western Prov­ince, opposite Sierra Leone. The dis­covery precipitated such a rush and such chaotic conditions that the gov­ernment was forced to close the area to prospecting and mining until mid-1958, when certain restrictions were imposed. The approximately 50-square-mile area does not appear to be exceedingly rich. The majority of the stones exported from Liberia, until very recently, were apparently those smuggled into that country from Sierra Leone and possibly Guinea. diamond production ex-


ported in 1 975 reported to be approx­imately 165,000 carats industrial and 241,000 carats gem quality.

Lichtenburg. A town in the Transvaal Province, Republic of South Africa, in which many alluvial diamond diggings are located. It was a major producing field from the time of its discovery in 1925 until 1929, but production has since declined sharp­ly. The production was below aver­age in quality, consisting primarily of cleavages and industrials. The large output from this field, plus the onset of the Depression, posed such a threat to price stability that the diamond Corporation, Ltd., was founded to buy stones in order to hold them off the market, thus stabilizing prices.

light brown. See brown diamond.

light cape. See cape.

light-field illumination. A type of il­lumination in which the light source is directly behind the diamond or other gemstone being observed. This principle, together with dark-field il­lumination, is incorporated in the Cemolite, or Cemscope (trademark, Gemological Institute of America) and the Diamondscope (trademark, American Gem Society).

Light of Faith diamond. See nur-ud

DEEN diamond.

Light of India diamond. One of two

large Diamonds (the other being the Rajah diamond) that belonged to the late Boston socialite, Mrs. Jack Gardner, which she had bought from Tiffany's in 1886. Listed in the bill of sale were two weights, 12.38 carats and 25.5 carats, but it did not specify to which diamond they belonged. Worn as a hair ornament, set on a spring, to wave about the head like


diamond

an antenna. Owned by another Bos-tonian; name undisclosed. See rajah

diamond.

 
Leveridge gauge Levinson Prospection Liberator Diamond PDF Print E-mail
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Friday, 21 September 2007

Leveridge gauge. A millimeter dial micrometer, designed by A. D. Leveridge, for measuring both mounted and unmounted Diamonds and colored stones of various styles of cutting. An accompanying set of tables is used for translating mea­surements into weights. It is the most accurate of the gauges designed specifically for weight estimations.

See MOE GAUGE, MILLIMETER SCREW MICROME­TER.

Levinson Prospection. A small dia­mond-mining concern that works diamondiferous terraces south of the Kunene River, which forms the fron­tier with Angola, in the extreme north of South-West Africa.

Liberator diamond. In honor of Simon Bolivar, nineteenth-century liberator of Venezuela, who was af­fectionately called El Libertador by his countrymen, this top-quality 155-carat diamond was given the name Liberator. It was discovered by three miners in 1942 in the Gran Sabana diamond-bearing region of Venezuela. Purchased in 1943 by Harry Winston, New York City gem dealer, it was cleaved into two pieces weighing 115 and 40 carats. These cleavages, in turn, were fashioned into four stones: three emerald cuts of 39.80, 18.12 and 8.93 carats, and a 1.44-carat marquise. Fifty-six per­cent of the original weight was lost in the cutting process. Winston used the three smaller stones in an elabo­rate clip and sold the 39.80-carat stone to Mrs. May Bonfils Stanton, Denver, Colorado, heiress and phil­anthropist, in 1947. In 1962, he ac­quired the stone a second time, purchasing it from the New York auc­tion galleries of Parke-Bernet, Inc., from the jewelry estate of Mrs. Stan­ton for $185,000. The Liberator is set in a platinum ring with two tapering diamond baguettes.

 
Lesotho B Diamond CULLINAN (II) DIAMOND Letny Diamond PDF Print E-mail
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Friday, 21 September 2007

Lesotho B diamond. This large rough weighing 527 carats was one of the three largest Diamonds ever found in Lesotho. It was discovered in 1965 and bought by Mr. E. J. Sera-fini of Bloemfontein and Maseru for $162,400. The Lesotho B was later resold to an unknown American dealer in Antwerp. Present disposi­tion is not known.

Lesotho C diamond. Discovered at the Kau diggings, Lesotho, in 1969, this large brown rough weighing 338 carats was initially sold for $54,740. It was reportedly cut into 10 stones in Amsterdam of which the largest gem


is a 24-carat marquise. The where­abouts of these Diamonds is un­known today.zesser

Star of Africa diamond. See

CULLINAN (II) diamond.

Lestergem. Trade name for synthetic spinel.

Letny diamond. A 46.36-carat rough found in Mirnyy, Yakutiya, Siberia, sometime after 1955. Now in the Russian diamond Fund at the Krem­lin.

Letseng-la-Terai pipe. diamond bearing kimberlite pipe in the Drakensberg Mountains of north­eastern Lesotho. Highest diamond diggings in the world at over 10,200 feet where snow covers the area for about three months a year and tem­peratures plunge to sub-zero. Some-


times spelled Letseng-la-Draai. The surface area of the pipe is about 20 hectares and is covered with a thin layer of black soil. Smaller satellite pipes surround the deposit. Several large Diamonds have been reported found at Letseng-la-Terai, significant among these are the pale brown col­ored 601.25-carat Lesotho diamond discovered in 1967, a 147-carat stone


in 1969, and a 155-carat off-white octahedron found in 1973.

 
Le Grand Sancy Diamond Le Grand Sancy Diamond Lesotho Lesotho Diamond PDF Print E-mail
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Friday, 21 September 2007

Le Grand Sancy diamond. See sancy

diamond.

Leicester Mine. A small diamond pipe mine in the Barkly West area, Cape Province, Republic of South Af­rica. It is owned by Carrig Dia­monds, Ltd.

Leopold diamond. A 10-carat bril­liant. Given by King Leopold III of Belgium to his late wife, Queen As-trid, mother of present King Bau-douin. Exhibited at Newark, New Jersey, Museum, 1948. Owned by an undisclosed private collector.

Lesotho. Prior to 1966, it was known as the High Commission Territory of Basutoland. Totally surrounded by the Republic of South Africa, Lesotho consists of a central high plateau with lowlands to the west and high­lands to the east with elevations up to 11,000 feet in the Drakensberg Mountains. Diamonds occur in the northern part of the country at the Letseng-la-Terai mine, and other pipes. De Beers is in the process of preparing this pipe for extensive min-



diamond areas of Lesotho

ing, despite a very low diamond production in terms of carats per load. The rationale is that there may be enough large stones to make the gamble worthwhile. diamond pro­duction in 1975 was reported to be 2,000 carats industrial and 1,000 carats gem quality.

Lesotho diamond. The Lesotho diamond was discovered in Lesotho, Africa, in May, 1967 by Mrs. Ernes­tine Ramoboa at the Letseng-le-Draai diggings. The brownish-colored rough weighed 601.25 carats and was sold for $302,400 at auction in Maseru, the capital of Lesotho, to a South African dealer. He, in turn, sold it to a European dealer. This diamond was later purchased in Ge­neva by Harry S. Winston of New York, who subsequently cut it into 18 stones totaling 242.50 carats, in 1969. Most diamond cutting styles

 
leakage Ledo Frozen Fire Lee Diamond Le Grande Conde' Diamond PDF Print E-mail
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Friday, 21 September 2007

leakage. Light leaving (refracting from) an optically dense medium is referred to as leakage. Planned leak­age is light departing a faceted gem from the crown to the eye. Un­planned leakage is light escaping a faceted gem from the pavilion, there­by being lost and not returned to the crown, and subsequently lost to the eye. See brilliancy, critical ancle, refrac­tion, TOTAL REFLECTION.

lean pipes. South African diamond pipes that cannot be profitably worked. See pipe.

Ledo Frozen Fire. A trademarked name for colorless synthetic corun­dum.

Lee diamond. The unofficial name for a 4.50-carat distorted octahedron that was found in Lee Co., Alabama, about 1900. It was owned and dis­played by the American Museum of Natural History, New York City; it was stolen in 1964 and never recov­ered.


Leeuwbosch. A minor alluvial dia­mond deposit in the Bloemhof area, Transvaal Province, Republic of South Africa. The yield from this dig­ging is insignificant. Leeuwfontein. An alluvial diamond deposit in the Wolmaransstad area, Transvaal Province, Republic of South Africa, the output of which is negligible.

Leeuwkraal. A minor alluvial dia­mond deposit in the Ventersdorp area, Transvaal Province, Republic of South Africa. This digging makes a very insignificant contribution to total South African alluvial produc­tion.

Le Grande Conde' diamond. The Grand Conde is one of the most unusual of the world's notable Diamonds: a light pink, pear-shaped stone of 50 carats. Agents of Louis XIII are said to have bought the stone in 1643, after which the King pre­sented it to Louis de Bourbon, Prince of Conde, who had distinguished himself as Commander of the French Army in the Thirty Years' War and


who became known as the Grand Conde'. Until his death in 1686, the Prince was known as an enthusiastic patron of the arts and an ardent ad­mirer of various charming women, one of whom described him as a much more effective and able gen­eral than paramour! The diamond remained in the Conde' family until the Due d'Aumale bequeathed it to the French Government in 1892. To­day, it is on display in the Musee de Conde in Chantilly, where, according lo the terms of the Due's will, it must always remain. It is also known as (he Conde diamond. Also named Grande Conde.

 
La Reine Diamond Lasarev Diamond Laser Gem PDF Print E-mail
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Friday, 21 September 2007

La Reine diamond. See queen of bel

(HUM diamond.

Larkin's Flat. One of the early allu­vial diamond diggings on the Vaal River, Republic of South Africa. La Rose diamond. See la rose pink

diamond.

La Rose Pink diamond. A 7.07-carat flawless marquise that was cut in 1954 and shown at the opening of the Sheridan Village Shopping Center in Peoria, Illinois, in March by Marks Bros. Jewelry Store. It was valued at $40,000. Alternate name is La Rose diamond.

Lasarev diamond. See orloff dia­mond.

laser. Acronym for Light Amplifica­tion by Stimulated Emission of Radia­tion. Lasers produce a special kind of light that is monochromatic, cohe­rent, and collimated. Laser systems have been used to enhance the clar­ity grade of Diamonds by providing passages to dark inclusions and to act as conduits for bleaching agents. See laser drilling.

laser drilling. Technique of enhanc­ing the clarity of a diamond by pro­viding access for bleaching agents to inclusions. Intense heat is generated by a focused laser beam which actu­ally burns into the diamond to or through an inclusion. Sometimes drilling a tiny hole (less than 5/ 1000ths of an inch in diameter) into a flaw may make it whiten and dis­appear. Usually, a special bleaching or leaching agent such as hydrofluor-


ic acid is needed to leach out the dark inclusion. See laser.

Laser Gem. Trade name for a com­posite imitation (doublet) diamond simulant consisting of a synthetic spinel top and a strontium titanate bottom.

lasque. See bevel cut.

lasque Diamonds. Very thin tabular Diamonds which in the past were used by Indian cutters to glaze mini­ature paintings and hence were call­ed portrait stones or lasques.

Last Hope. A minor alluvial diamond deposit in the Barkly West area, Cape Province, Republic of South Af­rica. The output from this mine in one recent year amounted to less than 300 carats.

lax diamond. A seldom-used term for a diamond with little fire and bril­liancy.

laxey Diamonds. Trade term for very shallow brilliant-cut Diamonds.

lead glass. Glass containing a high percentage of lead. The addition of

lead increases both the refractive index and dispersion, thus producing a more effective diamond imitation than ordinary crown glass. However, it is softer than crown glass. See paste.

 
La Belle Helene Diamond Lake George diamond Landak River lapper PDF Print E-mail
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Friday, 21 September 2007

La Belle Helene diamond. An ex­ceptionally fine 160-carat alluvial diamond. Found on the Orange River, Republic of South Africa in 1951. Bought by Romi Goldmuntz of Antwerp for £80,000 and named for his wife. Cut in the U.S. into three stones: matching pear shapes of 30.28 and 29.71 carats and a 10.50-carat marquise. All were sold pri­vately.

Lace (or Crown) Mine. A diamond mine of minor importance located about 100 miles south of Johannes­burg in the Kroonstad district, Orange Free State, Republic of South Africa.

La Favorite diamond. A top-quality 50.28-carat stone. Exhibited at Chi­cago World's Fair in 1934, when it was owned by a Persian and val­ued at $1,000,000. Present location unknown.

Lake George diamond. Same as Her­kimer diamond.

lambreu. A Brazilian term for irregu­lar diamond fragments.

Landak River. A source of early diamond deposits on the Island of alimantan, formerly called Borneo.

See KALIMANTAN.

lap. A flat, horizontal, diamond-dust-impregnated cast-iron wheel, 12 to 18 inches in diameter, that re­volves about a vertical shaft. It is used for grindingpolishing facets on Diamonds. Another name is scaife (also spelled skeif or skaif). diamond-charged laps, often made of other materials, are also used for industrial purposes and for fashion­ing colored stones. (See photo.) and

lapidary (or lapidist). A cutter, grind­er and polisher of colored stones. In the trade a lapidary is not necessarily an engraver of gems, this being con­sidered a specialized art. A cutter and polisher of Diamonds is classed as a diamond cutter, as distinguished from a gem cutter, or lapidary.

lapper. See blocker.

lapping. See blocking.

La Reine des Beiges diamond. A

50-carat diamond. Thought to have been owned by the Queen of Bel-

 
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