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Gemprint PDF Print E-mail
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Wednesday, 19 September 2007

Gemprint. An instrument designed and manufactured by KULSO, Ltd., Haifa, Israel, based on research of the Weizmann Institute of Science. The system uses a laser beam light source, produces a Gemprint photo­graph of the reflections of the polished surface of a faceted stone. Reportedly, faceted Gemstones of any size, mounted or not, may be re­corded (photographed) in this man­ner.

Gems & Gemology. The quarterly journal of the Gemological Institute of America.

Gemscope (trademark, Gemological Institute of America). Another name for Gemolite.

Gem-Trade Laboratories, Gemologi­cal Institute of America. The three research and testing laboratories that are maintained and operated by the GIA to provide gemstone, diamond, and pearl identification and grading for the jewelry industry, Better Busi

ness Bureaus, jewelers' organiza­tions, insurance companies and the public. They are located at 580 Fifth Avenue, New York City, New York 10036; 1660 Stewart Street, Santa Monica, California 90404; and 606 South Olive Street, Suite #1122, Los Angeles, California 90014. See Ap­pendix for more detailed informa­tion.

 
Gemological Institute of America PDF Print E-mail
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Wednesday, 19 September 2007

Gemological Institute of America. A

nonprofit, endowed, educational In­stitution controlled by jewelers and maintained for the benefit of the in­dustry and the public. In addition to courses in Diamonds, colored stones, jewelry designing and jewelry retail­ing, the Institute publishes books, pamphlets and periodicals, manu­factures diamond-grading, gem-test­ing and other instruments, identifies Gemstones and grades diamonds for the industry and the public. Classwork is offered in Santa Monica, New York City and cities throughout the country. Headquar­ters: 1660 Stewart Street, Santa Monica, California 90404. Eastern office: 580 Fifth Avenue, New York City, New York 10036. Midtown Los Angeles Gem Trade Lab: Suite 1122, 606 South Olive Street, Los Angeles,


California 90014. See Appendix for more detailed information.

gemologist. A specialist in gem materials. One who has successfully completed recognized courses of study in gem identification, grading, and pricing, as well as diamond grading and appraising; e.g., a Gemologist or Graduate Gemologist of the Gemological Institute of America or a Certified Gemologist of the American Gem Society or a Fel­low of the Gemmological Associa­tion of Great Britain. Gemmologist is the English spelling of gemologist. gemology. The science and study of gemstones; their sources, descrip­tions, origins, identification, grading, and appraising.

 
full-Dutch PDF Print E-mail
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Wednesday, 19 September 2007

full-Dutch (or full-Holland) rose cut.

A rarely used rose style of cutting that has a circular girdle outline, a


Full-Dutch (or full-Holland) rose cut.


flat, unfaceted base, and a pointed, dome-shaped crown bearing 24 tri­angular facets.

full gauge. Trade term for a finished stone approaching the proportions of the Tolkowsky theoretical brilliant.

full-Holland rose cut. An alternate name for full-Dutch rose cut.

fundos. A Brazilian term for broken or highly imperfect diamond crystals mixed with second-quality car­bonados.

furrow. Same as foss

. furrowed stone. See foss.

fuzzy girdle. See bearded girdle.

 
Friedlander PDF Print E-mail
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Wednesday, 19 September 2007

Friedlander, J. One of the early in­vestigators into the problem of diamond synthesis. In 1898, he dis­solved graphite in fused olivine and obtained small octahedral crystals he thought to be Diamonds. Later he ex­perimented with a mixture of metals that had the iron and magnesium content of kimberlite, with graphite as a source of carbon, in a thermite reaction. He found that an addition of titanium dioxide helped in the formation of the tiny crystals. How­ever, there is no proof that the crys­tals were diamonds. See synthetic

DIAMOND.

frosted crystal. A diamond crystal having a frosted appearance.

FTC. See federal trade commission.

full-cut brilliant. A term used cor­rectly for a brilliant-cut diamond or colored stone with the usual total of 58 facets, consisting of 32 facets and a table above the girdle and 24 facets and a culet below. On colored stones the girdle is usually polished,

 
French Coral Diamond PDF Print E-mail
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Wednesday, 19 September 2007

French Coral diamond. A yellowish 7.25-carat rough stone reportedly discovered in Nevada County, Cal­ifornia. Date and ownership unknown. French cut. A square form of cutting with a square table, the edges of



which, rather than being parallel to the edges of the girdle outline, are placed at 45° to it. Facets other than the table may vary in number and shape.

French Equatorial africa. A former French African colony before the es­tablishment of the present indepen­dent nations of gabon, Republic of Congo (formerly Moyen, or Middle, Congo), Central African Republic and Chad. Diamond production is entirely alluvial and is concentrated in the Central African Republic, al­though Gabon is a minor producer. Prospecting is being undertaken elsewhere. The principal producing companies are Compagnie Miniere de I'Oubangui Oriental (CMOO), Societe de Recherches et d'Exploi-tation Diamantiferes (SOREDIA), Societe Miniere Intercolonial (SMI), Compagnie Miniere de Carnot, Societe Miniere de I'Est Oubangui, and S.A. de Recherches et d'Exploita-tions Minieres Centre Oubangui (SAREMCO). As in French West Af­rica, the percentage of industrials is approximately 66%. Annual produc­tion is on the order of 100,000-150,000 carats.

French Sudan. See mali federation.

"French West Africa." A former French colonial grouping that was made up of a number of smaller col­onies, including Mauritania, Senegal, Guinea, Ivory Coast, Dahomey, Upper Volta, French Sudan and Niger. Of these, Guinea and Ivory Coast, now republics, are the princi­pal diamond producers. The alluvial mines of Guinea are similar to those of Sierra Leone, and are probably extensions of the latter fields. The


most important mines are in Haute-Guines, midway between Beyla and Kissidougou. The mining companies are Societe Cuineenone de Re­cherches et d'Exploitations Minieres (SOCUINEX), Societe de Recherches et d'Exploitations Minieres en Cote d'lvoire (SAREMCI), Societe Miniere de Beyla, and Societe Diamantifere de la Cote d'lvoire (SODIAMCI). Na­tive miners also work alluvial dig­gings in the same area, exporting much of their production to Liberia illegal channels. Total an­nual production varies from approx­imately 200,000 to more than 300,000 carats. The proportion of industrials is about 66%. through

 
Frank Smith Mine PDF Print E-mail
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Wednesday, 19 September 2007

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

Fraunhofer lines. A group of dark lines (absorption bands) crossing the solar spectrum resulting from absorp­tion of light by the vapor of elements in the sun's chromosphere. Named for their discoverer, Joseph Fraunhof­er, in the 19th century, who desig­nated the principal lines by letters of the alphabet. The important lines are given in Angstrom units: A, 7606; B, 6870; C, 6563; D, 5893; E, 5270; F, 4861; G, 4308; H, 3969. The dispersion, i.e., the difference in refractive index of diamond, is mea­sured between the B and G Fraun­hofer lines. See dispersion.

French Blue Diamond. The French Blue was a 69.03-carat diamond that was believed by gem historians and now corroborated by H. Tillander, in his study of "The Hope Diamond


and Its Lineage" (1975), to have re­sulted from the cutting of the 110.50-carat Tavernier Blue. Taver-nier, the noted French jeweler and traveler, reportedly first saw the diamond in India in 1642 and later brought it to France. He sold the stone to Louis XIV and, later, Pitau, the Crown Jeweler of the King, recut it to a 69.03-carat "heart shape." It was once the center stone in the Flame of a Golden Fleece. In 1791 it entered the inventory of the Crown Jewels in the French Royal Treasury (Garde Meuble) where it. remained until the great gem robbery of Sep­tember 17, 1792. Because of its peculiar blue color, some gem histo­rians once believed that it was perhaps recut again, producing the world-famous Hope and the Bruns­wick Blue. However, their combined weights are too close to that of the French Blue to make this plau­sible. Tillander's recent study in­dicates that the Hope Diamond originated from the French Blue and that the Brunswick Blue must have come from another source. Also known as Blue Diamond of the Crown. See hope diamond, tavernier blue

DIAMOND.

 
four-square stone framesite bort PDF Print E-mail
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Wednesday, 19 September 2007

four-square stone. See blocker, fracture. A term used to describe the chipping or breaking of a stone along a direction other than a cleavage plane. Types of fracture include con-choidal (kahn-koy"-dal), or shell­like; splintery; granular; even; and uneven. diamond has a distinct frac­ture, as well as cleavage, although it is less commonly seen because the cleavage develops so easily. It usu­ally occurs in conjunction with cleavages, forming an irregular step­like pattern.

framesite bort. A coarse, gritty, rather friable, black, nongem quality of diamond found primarily in the Premier Mine, Republic of South Af­rica. See bort

Frankfurt Solitaire Diamond. In

1764, Francis I, Grand Duke of Tus­cany, purchased a fine-quality brilliant-cut diamond, weighing ap­proximately 45 carats, and had it mounted in his hat buckle. The lovely brilliant came to be known as the Frankfurt Solitaire. After the death of Francis, the Empress Maria Theresa had all of her late consort's private jewelry placed in the Royal Treasury for safekeeping; later, how­ever, the stone was brought out and set in a diamond tiara. In 1918, the Austrian Royal Family took many of the Crown Jewels to Switzerland when they went into exile; among them was the Frankfurt Solitaire. About 1920, it was thought to have been stolen by a person close to the Family and taken to South America with other gems from this historic collection. Today, the location of this stone is unknown.

 
foilback PDF Print E-mail
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Wednesday, 19 September 2007

foilback. An inexpensive gemstone or a piece of faceted glass that has been backed with a thin leaf of metallic foil, either silver or other color, to simulate the brilliancy of a diamond or to impart or improve the color of a colored stone. Forlorn Hope. One of the early allu­vial diamond diggings on the Vaal River, Cape Province, Republic of South africa. Now an insignificant producer.

form-and-profile diamond dressing tool. A single-diamond dressing tool for trueing special radial and step forms. It may contain either an uncut diamond crystal or a lapped dia­mond.

Forminiere. See l'office forestiere et

MINIERE DU CONGO.

Forty-Seventh Street. The present-day center in New York City of the diamond and jewelry industry of America.

foss. An irregular furrow or groove on a diamond crystal. Fosses are characteristic of crystals in the gray color range.

Four C's. A coined phrase for adver­tising purposes that restricts the numerous factors affecting diamond value to four terms: cutting, color, clarity, and carat we/grit. See quality,

FACTORS THAT DETERMINE.

four grainer. See grainer.

four-point diamond. (1) A diamond that weighs four one-hundredths of a carat. (See point). (2) A diamond whose table has been cut parallel to a possible face of the cube.

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

Flower diamond. A 1.95-carat en­graved diamond. Owned by Arthur Fine of Max Fine & Sons, Inc., New York City diamond cutters.

fluorescence (floo'-oh-res"-cence).

A variety of luminescence. The property of changing one kind of radiation to another; for example, the visible wavelengths emitted by a material when excited by invisible radiation such as X-rays, ultraviolet rays or cathode rays, as well as by certain other visible wavelengths. It is exhibited by ruby, kunzite, yellow-green synthetic spinel, some


Diamonds and opals, and many oth­er substances. Diamond usually fluoresces blue, although occasional stones may glow light red, green, orange, yellow or subtle variations of these. If the fluorescence is suffi­ciently strong to alter the color of the stone when observed alternately under incandescent light and day­light, it is said to be fluorochromatic.

See LUMINESCENCE, PREMIER DIAMOND, PHOS­PHORESCENCE, PHOTOLUMINESCENCE, UL­TRAVIOLET, ULTRAVIOLET LAMP EMISSION SPEC­TRUM, FLUOROCHROMATIC, CATHODOLUMINES-CENCE.

fluoride coating. Coating used to temporarily improve the color of diamonds. Applied by vacuum sput­tering to form coatings of only a frac­tion of wavelength in thickness. Sometimes recognized by irides­cence of the surface.

fluorochromatic (floo'-row-kro'-mat"-ik). When fluorescence causes a diamond to change color when exposed alternately under two differ­ent kinds of visible radiation, such as incandescent light and daylight, it is said to be fluorochromatic; for example, a yellow stone that displays sufficiently strong blue fluorescence in daylight to make it appear bluish.

See FLUORESCENCE, PREMIER DIAMOND, TRANS-ICHROMATIC.

Fly Diamond. A 60-carat rough diamond reported to be a white oc­tahedron was discovered in 1872 on the claim of Robert Spaulding and Antoine Williams at Waldeck's Plant, Vaal River, Cape Province, Republic of South africa. The Stewart or Spaulding Diamond was also discov­ered at this site by the same two prospectors. It is said that an inclu-

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

Florentine diamond. Once the great yellow diamond of the Medici Fam­ily, this historic Indian stone is actu­ally light greenish yellow in color and is fashioned in the form of an ir­regular, nine-sided, 126-facet double rose cut. It weighs 137.27 carats. Legends surrounding the stone date as far back as 1467, when Charles the Bold, Duke of Burgundy, is said to have been wearing it when he fell in battle. A peasant or foot soldier found it on the Duke's person and sold it for a florin, thinking it was glass, after which it changed hands innumerable times for small sums of money. Pope Julius II is named as


one of the owners. Authentic history begins when Tavernier, the famous French jeweler and traveler, saw the stone among the treasures of the Grand Duke of Tuscany in 1657. When the last of the Medici's died, it passed to Vienna through the mar­riage of Francis Stephan of Lorraine (who later became the Grand Duke of Tuscany) to Empress Maria Theresa and was placed in the Hapsburg Crown. Later, it was displayed in a brooch among the Austrian Crown Jewels in the Hofburg, Vienna; at that time, it was valued at $750,000. After the fall of the Austrian Empire, during World War I, the Florentine was taken by the Imperial Family

into exile in Switzerland. Later, it was thought to have been stolen by a person close to the Family and taken to South America with other gems from the Crown Jewels. After this, it was rumored that the great diamond was brought into the United States in the 1920's and was recut and sold.

As a matter of record, it must be listed with other "lost" renowned Diamonds of the world. Officials at the Kunsthistorisches Museum in Vienna, where the Florentine was on display prior to 1918 in a hat orna­ment, stated to the Gemological In­stitute of America in 1964 that they have no knowledge of the stone's present location. Alternate names are the Tuscan, the Grand Duke of Tus­cany, the Austrian Diamond, the Aus­trian Yellow Brilliant, and the Aus­trian Yellow.

Last Updated ( Wednesday, 19 September 2007 )
 
Fleischman Star Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Fleischman Star diamond. A 74.44-carat emerald-cut canary diamond purchased by Harry Winston, New York City gem merchant, in 1956. It was recut to 71.07 carats, and set in a clip-pendant combination with 32


brilliants weighing 13 carats. The Fleischman Star Diamond was sold through the Paris branch of Harry Winston, Inc., in 1957.

Flinders diamond. A misnomer for colorless topaz from Tasmania.

floating reef. Inclusion of the sur­rounding rock found in kimberlite in a diamond mine. See kimberlite, reef

. floor (or weathering floor). A name given to the flat area on which the hard diamond-bearing rock (kimber­lite) was once weathered as a step in the recovery process. Weathering, which will disintegrate kimberlite, was a practical step in the early days of diamond pipe mining, because near-surface rock tended to disinte­grate more rapidly than that mined at greater depths. In addition, the mill­ing equipment was cruder, and the fear of destroying large rough Diamonds was greater. The large in­vestment in mined but nonproduc­tive blueground and the added han­dling gradually led to the abandon­ment of this method.

 
flawless PDF Print E-mail
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Wednesday, 19 September 2007

flawless. The recommended term for a diamond without external or inter­nal flaws or blemishes of any de­scription when viewed by a trained eye under efficient illumination and under a fully corrected magnifier of not less than 10 power; binocular examination under dark-field illumi­nation is preferred. The American Gem Society advocates the use of the term flawless by its members, while at the same time denying them the use of the term perfect. The Fed­eral Trade Commission "permits the use of the term flawless, but only if a stone conforms to its definition of the word perfect, without reference to make or color. See aberration, clarity

(OR IMPERFECTION) GRADE, PERFECT.

 
Flame of Cold Diamond Flaming Star Diamond Flat Creek Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Fl. The abbreviation for flawless, the top clarity, or imperfection grade of diamond.

Flame of Cold Diamond. A 29-carat pear-shaped canary diamond which was in a necklace designed by Ann Samols, designer for Julius Cohen, that won the 1957 Diamonds-In­ternational Awards. It was bought from the firm of Julius Cohen in 1963 by Mr. Buddy Fogelson as a Christ­mas gift for his wife, Greer Garson. No other details are available.

Flaming Star Diamond. This unique 18.52-carat pear-shaped stone is a fine white color under normal light and glows a very intense brilliant orange color under ultraviolet light. It was cut from an 88-carat rough re­covered from the De Beers Mine. Baumgold Brothers of New York City purchased and polished the stone in 1967. It is reportedly still owned by Baumgold Brothers and valued at approximately $500,000.

Flat Creek Diamond. A 1.81-carat rough white diamond found in Union County, Tennessee. No other details are known.

flats. A term used in the rough-diamond trade for flat diamond crys­tals or portions thereof; they may or may not be portions of mac/es.

flat stone. A diamond brilliant with a very thin crown and pavilion. See

TOLKOWSKY THEORETICAL BRILLIANT CUT.

flaw. A general term used to refer to any Internal or external characteristic on a fashioned diamond; e.g., a feather, fissure, carbon spot, knot, etc. Some diamond men limit its use to internal faults only, using the term blemish for surface faults. The terms flaw and imperfection are usually

 
fire PDF Print E-mail
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Wednesday, 19 September 2007

fire. Flashes of the different spectral colors seen in Diamonds and other Gemstones as the result of dispersion. See dispersion.

first bye. A color-grading term used at the mines to indicate the finest quality of byewater stones. See bye.

first water. See water.

fisheye. A diamond whose pavilion is exceedingly shallow, producing a glassy appearance and a noticeable dearth of brilliancy. Girdle reflection appears inside the table of the stone


when viewed through the table. See

SHALLOW STONE.

fissure. An elongated cavity in a diamond's surface. It may or may not have occurred along the line where a cleavage reached the surface.

 
Fineberg-Jones Diamond PDF Print E-mail
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Wednesday, 19 September 2007

Fineberg-Jones diamond. A fine-quality 206-carat crystal. Found in 1911 on the Vaal River, Cape Pro­vince, Republic of South africa. Pres­ent whereabouts unknown.

fine cleavage. A term sometimes used in the classification and grading of rough Diamonds for fine-quality cleavage pieces.

fine silver cape. See cape

finest water. See water

fine water. See water.

finish. Cutting quality is judged not only by the proportions and facet an­gles of a diamond, but -by the ex­cellence of its polish, the smoothness of its girdle surface, the exactness of its symmetry, and the size of its culet. These details of cutting constitute a fashioned stone's finish. In some diamond-grading systems, imperfec­tion or clarity grading is divided into two categories: internal and external grades. In such a system, the external grade is synonymous with finish quality. See American cut; cutting; pro­portions, GOOD; SYMMETRY; TOLKOWSKY THEORETICAL BRILLIANT CUT

Finsch Mine. The prospect was dis­covered by A. T. Fincham, an inde­pendent prospector, in the desert-like Postmasburg area about 100 miles north-east of Kimberley. In 1963, his rights were bought out by De Beers for 2:/4 million pounds. Later the property became the Finsch Mine, named after Fincham and his partner, E. Schwabel. The Finsch Pipe is about 45 acres in area. The blue ground is overlain by about 300 feet of yellow ground containing ironstone and mixed kimberlite. It is an excellent example of systematic open-cast or open pit mining. At


about 900-foot depth, the company will cease surface mining operations and will begin mining by under­ground methods. The total produc­tion in 1974 was 2,353,413 carats.

 
fezel PDF Print E-mail
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Wednesday, 19 September 2007

fezel (faizel). White streamer-like feathers ("intergrowths" on the twin plane) especially seen in a stone cut from a made.

Fiery Astrolite. Trade name for man-made lithium metaniobate.

fifth. A common abbreviation for a fifth carat.

fifty-nine-twenty line. A sharp ab­sorption line seen in the spectrum of most yellow and brown Diamonds in which the color has been imparted artificially by neutron bombardment and subsequent heat treatment. The application of this line (5920 A) to the detection of such diamonds was first described by Robert Crown-ingshield in Gems & Cemology, Vol. IX, No. 4. See absorption spec­trum.

Fifty Years of Aeroflot diamond. Named in commemoration of Soviet Aviation Day, this diamond, weigh­ing 232 carats, was found in the dia­mond field of Mirnyy in the Yakut-skaya region of Siberia. Discov­ered in August, 1973, it became the largest known Soviet diamond. Within three months, however, another diamond of identical weight, The Star of Yakutiya, was reportedly found in the same area.

file test. A test that is used princi­pally to separate glass imitations from diamonds, since a jeweler's file (hardness about 6V2) will scratch glass but not diamond. However, many natural and artificial stones that might be confused with dia­mond are harder than a file and thus cannot be separated from diamond by such a test. In addition, the thin edges of a diamond may be damaged by the test.

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

Ferdinand diamond. According to a writer in 1882, this diamond was a 42-carat flawed Indian stone found in the early seventeenth century and taken to Venice by one Edward Fer­dinand for cutting. During the early stages of the fashioning process, it broke into numerous pieces. Further details are lacking.

Ferouba. An important alluvial dia­mond deposit in Guinea, on which Societe Cuineenone de Recherches et d''Exploitations Minieres (SOCUIN-EX) has had an exploitation concession. See guinea.

fervidor (or canoa). A Brazilian term for a primitive and little-used method of separating Diamonds from worth­less gravel.

 
Federal Trade Commission PDF Print E-mail
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Wednesday, 19 September 2007

Federal Trade Commission (FTC). A

United States Government body that oversees interstate commerce and cooperates with representatives of various industries, including the dia­mond and jewelry trades, to pro­mote trade-practice rules governing the representation to the public of the products of those industries.

felsic. (1) a mnemonic adjective de­rived from (fe) for feldspar and (s) for silica and applied to light-colored igneous rocks, e.g. granite. (2) Also applied to felsic minerals, e.g. quartz, feldspars, feldsphathoids, and muscovite. (3) Synonym for acidic; a misleading term used for light-colored igneous rocks. See igneous

ROCK; ACIDIC IGNEOUS ROCK; SILICIC.

 
faultless PDF Print E-mail
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Wednesday, 19 September 2007

faultless. A less-commonly-used term than flawless, but having essen­tially the same meaning. As a word approximately synonymous with flawless, it is subject to the same re­strictions under Federal Trade Com­mission Trade Practice Rules. See

FLAWLESS, PERFECT

faulty structure. Zones of improper crystallization and internal cleavages and fractures are all considered un­der faulty structure. The cause may be disturbances during the growth of the crystal or later separations.

favas. A Brazilian term used to de­scribe the grains of gem minerals found in placer deposits. Also refers to the deposits themselves.

fazenda fina. A Brazilian term that is used to describe small, slightly tinted but otherwise fine-quality diamond crystals.

feather. A feather is a cleavage or a fracture that has a feathery appear­ance when viewed at right angles to the separation plane. A feather that appears white to the grader is often called a glets in the trade. Hairline


feather is a cleavage or fracture that is so shallow that it appears to be a scratch at first glance, but extends a short distance into the diamond. See

CLETS, FRACTURE, CLEAVAGE.

 
fancy diamond fan-shaped cut fashioning PDF Print E-mail
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Wednesday, 19 September 2007

false diamond. A misnomer for rock crystal.

false facets. A little-used term for extra facets.

Falun brilliants. Trade name for im­itation Diamonds made of lead glass. fancy cut. Any style of diamond cut­ting other than the round brilliant or single cut. Fancy cuts include the marquise, emerald cut, heart shape, pear shape, keystone, half moon, kite, triangle and many more. Also sometimes called fancy-shaped diamond or moderne cut.

A



fancy diamond. Any diamond with a natural body color strong enough to be attractive, rather than off color. Red, violet, blue, pink, and green are


the rarest; orange, strong yellow and yellowish-green stones are more common. Brown and black also are included in the fancy category. See

BODY COLOR, COLORED DIAMONDS.

fan-shaped cut. A little-used style of cutting that resembles a partly opened fan.


fashioning. A general term for the operations such as cleaving, sawing, rounding up, grinding and polishing that are necessary to transform a rough diamond into a cut-and-polished gemstone. See cutting.

fault. A little-used term that is essen­tially synonymous with flaw and im­perfection.

 
face up well PDF Print E-mail
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Wednesday, 19 September 2007

face up well. Many Diamonds in the intermediate color grades that show color readily in the edge-up position appear to be without noticeable color when viewed table up. Such stones are said to face up well. The bright, mirrorlike reflections of the light source in this position mask slight tints of color. For example, some well-cut stones that grade in the top cape grade, and most of those that fall in the crystal and top-crystal categories, seem colorless or nearly so under a strong white, light source when observed face up. See

EDGE UR FACE UP COLOR.

Fairvalley. A minor alluvial diamond deposit in the Barkly West area, Cape Province, Republic of South Af­rica. Current production is negligi­ble.

Faith Diamond. This stone, reported exceptional in size, was one of the earliest discoveries in 1871 at the old De Beers Mines. It was named the Faith Diamond by the brother of Olive Schreiner, a South African writ­er, because the discovery of the stone was attributed as an answer to a prayer.

false-colored diamond. A little-used


 
Fabulite PDF Print E-mail
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Wednesday, 19 September 2007

Fabulite (trademark). Trade name for man-made strontium titanate. face. (1) A term used in brillianteer-ing for the entire group of facets that can be placed on a diamond without repositioning it in the dop; viz., two star facets and four upper-break facets or four lower-break facets. (2) In crystallography, a natural, plane surface on a crystal. facet (fas"-et). A plane, polished sur­face placed on a diamond or other gemstone. See brilliant cut (round). faceted girdle. See girdle facet,

POLISHED GIRDLE.

faceting. The operation of placing facets on a diamond or other gem. See cutting.

face up. A diamond oriented with the table facing toward the viewer, the usual position in which a mounted stone is observed. (See photo.)

face up color. Color observed in a diamond when viewed from above

in a direction perpendicular to the table. When viewed with the table up, some stones appear without noticeable color because of a mask­ing effect caused mainly by the bril­liancy of the diamond and partially by surface reflections. Color be­comes visible in mounted goods, in the face up position, at about "J" or "K" color. See face up well.

 
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