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polished goods polished rough polisher polishing mark PDF Print E-mail
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Sunday, 23 September 2007

polished goods. Diamonds that have been cut and polished, as opposed to rough. See goods.

polished rough. A fashioned dia­mond whose shape and facets are to­tally unsymmetrical. See cap cut

polisher. A term used to describe any workman who places and polishes any of the facets on a diamond.

polishing. The reduction of a rough or irregular surface to a smooth flat­ness or curvature. In diamond fash­ioning, it is used to include both lap­ping, or blocking, and brillianteering, as well as the production of any facet; the final operation in fashion­ing a diamond, usually done with dia­mond powder on a horizontal disc, or lap, against which the diamond is held in a dop. See blocker, lapper, bril­lianteering, LAP DOR

polishing directions. The directions in which diamond polishes most eas­ily. In practice, this direction is usu­ally found by trial and error, although it is always away from an octahedron face and toward a possible rhombic-dodecahedron face. Facets parallel to the surface of a dodeca­hedron are the easiest to polish; those parallel to a face of an oc­tahedron are the most difficult. The ease and rapidity of polishing also varies in different directions; i.e.,


from right to left the rate may be more rapid than from left to right. See directional hardness.

polishing mark. A groove or scratch left by the polishing wheel on a facet of a diamond. Polishing marks do not run across facet junctions. Paral­lel grooves left during the initial plac­ing of facets should be removed dur­ing the final polishing to the point that they are not visible under 10x. Polishing marks are considered to be defects in finish.

polycrystalline diamond. Explosion synthesized Diamonds are hexagonal in structure and polycrystalline, i.e., they are composed of many crystals and are very hard, like carbonado. polysynthetic twinning. A form of repeated twinning, in which the twinning planes of adjacent indi­viduals are parallel. The result is a system of thin laminae, with each individual reversed with respect to the next. Polysynthetic twinning is thought by some to be the cause of the laminated effect that is seen in


some Diamonds under magnification. See twinning lines, knot lines, repeated twinning.

 
point naif Polar Star Diamond PDF Print E-mail
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Sunday, 23 September 2007

point naif (pronounced "knife"). A

term used by Tavernier in the 17th century to indicate a diamond oc­tahedron or other crystal shape hav­ing easily distinguishable natural faces. However, the term natural


point is now used in the industrial-diamond industry to mean an elon­gated diamond crystal, particularly one with sharp points. See naif. polariscope. An optical instrument that consists basically of two polariz­ing filters. The filter through which light enters is called the polarizer; that through which observations are made is called the analyzer. The in­strument is used to ascertain whether a gemstone possesses single or dou­ble refraction. It is also used to detect anomalous double refraction, which, when found in a singly refractive stone such as diamond, often indi­cates internal strain. See isotropic,

ANISOTROPIC, ANOMALOUS DOUBLE REFRAC­TION, REFRACTION, INTERNAL STRAIN.

Polar Star diamond. In layman's language, the 41.36-carat Polar Star has been described as the "brightest" diamond ever seen — a stone of in­comparable beauty and luster. Very little is known of its background, al­though it is thought to be of Indian origin. It is said to have belonged to Joseph Bonaparte, eldest brother of Napoleon I, who reputedly paid $10,000 for it. Joseph was King of Naples from 1806 to 1808, King of Spain from 1808 to 1813, and lived in the United States from 1815 to 1841. In the 1820's, the Polar Star was sold into Russia. Prince Yous-soupoff, who was living in France in 1949, stated at that time that the gem had been owned by his family for more than 100 years but was later sold to Carrier of Paris. It is now the property of Lady Lydia Deterding, Russian-born former wife of the late oil magnate, Sir Henry Deterding. The Polar Star is presently set in a ring, but detaches to form a pendant. Alternate name: Youssoupoff Dia­mond.

Pole Mine. An early diamond pipe mine in the Kimberley, Republic of South Africa area, located north of the city of that name.

polish. The relative smoothness of a surface, or the degree to which the finish of the surface approaches opti­cal perfection. A well-polished dia­mond shows no wheel marks or other surface blemishes under 10x.

 
Plymouth Diamond Pniel Pniel Estate Pohl Diamond Pointe de Bretagne Diamond PDF Print E-mail
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Sunday, 23 September 2007

Plymouth diamond. This 2.65-carat rough white diamond was discov­ered in 1934 at Amador County, California. Additional details are lacking.

Pniel. South African alluvial dia­mond diggings on the Vaal River, northwest of Kimberley, originally granted by a Koranna tribal chief to the Berlin Missionary Society. Begin­ning in 1870, the Society paid monthly lease fees of 10 shillings a claim. The finds were phenomenal. Consecutive prospecting began in June, 1870. Many claims yielded down to bedrock, 25 feet below the surface. Now called Pniel Estate, it is a minor producer.

Pniel Estate. See pniel pocaol. A Brazilian term for pits in river beds in which diamond-bearing gravel is found. See pothole.

"pocket peddler." A trade term that refers to sellers of Diamonds and other jewelry who operate without the benefit or cost of maintenance of an office or store.

Pohl diamond. A fine-quality, 287-carat alluvial diamond that was found by Jacobus Jonker (who also found the jonker diamond at the same time and place) in January, 1934, in the Elandsfontein diggings, near Pretoria, Republic of South Af­rica. The stone was cut by Lazare Kaplan for its owner, Harry Winston, New York City gem dealer. The largest stone cut from the rough,


which was reported sold to an opera singer, was an emerald cut that weighed between 40 and 50 carats. Also known as the De Pohl Dia­mond.

point. (1) In weighing Diamonds, one hundredth part of a carat, each one hundredth being called a point; e.g., 32 hundredths (0.32) of a carat is called 32 points, and a diamond weighing 0.32 carat is said to be a 32-point diamond, or a 32-pointer. (2) The sharp end or tip of a pear shape or marquise diamond. See

MARQUISE, PEAR SHAPE.

point cut. Believed to be the earliest form of diamond fashioning, consist­ing of simply polishing the natural faces of an octahedron. Also called diamond point. This cut is no longer used.

Pointe de Bretagne diamond. The

great diamond (weight unrecorded) of the French House of Dunois. Set with hanging ruby drops. Francis I, who initiated the Crown Jewels of France as a permanent collection, wore the diamond and drops in his cap. Further information lacking.

Pointe de Milan. A point-cut dia­mond. Part of the dowry of Catherine de Medici, niece of Pope Clement III, when she married the future King Henry of France in 1533. She gave it to her daughter-in-law, Mary Stuart, afterward Queen of Scotland, who married Francis II of France in 1559. Additional historical details lacking.

 
pique Pirie Diamond Pitt Diamond PDF Print E-mail
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Sunday, 23 September 2007

pique (pee-kay"). From the French meaning pricked. A term used by some importers as an imperfection grade. The original use of the word was confined to those stones that had tiny, difficult-to-find inclusions. It has been used with increasingly poor stones until 1st, 2nd and 3rd pique grades now sometimes fit in between or replace slightly imperfect and imperfect. Some importers still use the terms 1st, 2nd and 3rd pique for grades just below flawless or per­fect, and others for categories of the imperfect grade. Sometimes ab­breviated RK. See clarity grade; rk.

Pirie diamond. A one-carat blue di­amond bought by Edwin W. Streeter in Paris in 1877. Streeter believed that it came from the recutting of the French Blue. Its present whereabouts is unknown and no other historical details are available.

pit. An indentation on the surface of a diamond. It may be caused by a blow or by a knot being pulled out from the surface during the polishing operation. A fairly large indentation is usually called a cavity; a minor one, a nick. See percussion mark.

Pitt diamond. See recent diamond.

P.K. An abbreviation often used for pique. See pique, clarity grade.

placer. Alluvial deposit of heavy minerals concentrated on the surface by moving water or air. Usually a loose mass of gravel, sand, or similar material resulting from the crumbling and erosion of solid rocks containing valuable minerals such as gold, platinum, tin, Diamonds, and other Gemstones. In most cases the gems or metals can be collected by washing or amalgamation without milling. See alluvial

planned leakage. See leakage.

Platberg diamond. Although dia­monds have been reportedly found in Africa prior to 1860, one of the first documented stones is the Plat­berg diamond. Its occurrence is re­corded in the daily diary of the Pniel Station of the Berlin Mission Society. This 5-carat stone was found by a na­tive in 1859 on the riverbank of the Vaal River near Platberg, Republic of South Africa. It was later purchased by a Mission priest for £5. Its present whereabouts is unknown.

Pliny the Elder. A Roman naturalist and one of the earliest authors to de­scribe the diamond (77 A.D.): "a

 
pink diamond Pionersky Diamond pinpoint PDF Print E-mail
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Sunday, 23 September 2007

pink diamond. A fancy diamond. A lerm often used loosely in the trade lo describe any light red, light purple or light purplish-red diamond. Those olher than light red are sometimes described by such terms as rose pink, iose colored, peach blossom and heliotrope. See le grand conde' dia­mond, PEACH-BLOSSOM diamond, WILLIAMSON diamond, NUR-UL-AIN diamond, DARYA-I-NUR HIAMOND, PRINCIE diamond, WINSTON PINK NIAMOND.

pinpoint. (1) Any small rounded in­clusion seen at 10x but not large


enough to be discernible as an in­cluded crystal. (2) Essentially, the same as "carbon spots" which are somewhat more likely to be opaque.

Pionersky diamond. One of many large (weight unreported) named rough diamond crystals in the Rus­sian diamond Fund at the Kremlin.

pipe. The common name for a verti­cal, cylindrical or columnlike mass of rock that cooled and solidified in the neck of a volcano. When these rock masses are composed of kimberlite, they sometimes contain dia­monds. Although the kimberlite in the various pipes is similar, the pipes Ihemselves differ in size and shape and in the kind of Diamonds they produce. Kimberlite pipes occur in Arkansas, India, the Republic of South Africa, the Republic of Zaire, Russia and elsewhere. See kimberlite.

 
Pigott Diamond pile pile-treated dimond Pindar Diamond PDF Print E-mail
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Sunday, 23 September 2007

Pigott diamond. It was in the year 1818 when Ali Pasha of Janina, ruler of Albania and an enthusiastic gem collector, decided to purchase a large diamond from the London jewelry firm of Rundel & Bridge for $150,-000. Apparently, he was jealous of his newly acquired bauble and kept it in a little green leather bag inside his sash, seldom showing it to others. In 1822, the Sultan of Turkey, over­lord of Albania, became resentful of Ali Pasha's mounting power and in­dependence and sent an emissary to demand his surrender. The 80-year-old Pasha was mortally wounded in the palace scuffle that ensued. As he lay dying in his own throne room, he summoned a faithful soldier of fortune, a Captain d'Anglas, and or­dered him to destroy his two most precious possessions: the diamond and his wife, Vasilikee. Although the stone was reported shattered before his eyes, he failed to live long enough to insist on his wife's death and she escaped. This ill-omened stone, called the Pigott, was a fine-quality, oval-shaped Indian diamond, variously said to have weighed from47 to 85.80 carats. Most authorities agree to 49 carats. It was named for Baron George Pigot (the correct spell-int of the name), twice Governor of Madras, who was thought to have acquired it as a gift from an Indian prince in 1763 and willed it to a sis­ter and two brothers in 1777. Sub­sequently, it changed hands several times (once by lottery in 1801) and was said to have been owned at one time by Madame Bonaparte, mother of Napoleon. Since the death of Ali Pasha, there has been no trace of the Pigott; likewise, there is no actual evidence of its destruction. Only the model, which had been made previ­ously in England, remains. A less fre­quently used name is the Lottery Di­amond; an alternate spelling is Pigot.

See QUEEN OF ALBANIA diamond.

pile. A term used for the first nuclear reactor made by piling up graphite blocks and pieces of uranium and uranium oxide. See pile-treated dia­mond.

pile-treated diamond. A diamond whose color has been changed to green or yellowish green (or, if treated too long, to black) by bom­bardment with neutrons in a radioac­tive pile. Subsequent heat treatment may result in still further color change. See pile, nuclear reactor, cy­clotron TREATED.

Pindar diamond. Sir Paul Pindar brought this stone to England from Constantinople and sold it to Charles I. Valued at $150,000. Thought to have been among the royal jewels on which Henrietta Maria, his wife, raised $10,000 in one year. Sub­sequent history lost.

 
Piaui picotite piedra del cabo Piermatic Automatic Diamond Polishing Machine PDF Print E-mail
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Sunday, 23 September 2007

Piaui. A state in Brazil and a minor producer of Diamonds. See brazil. picking table. A flat or slightly in­clined platform on which diamond-bearing ore is distributed to remove unwanted materials. It was used in the South African diamond mines until the effectiveness of grease sep­aration was discovered accidentally. It is still used in some small opera­tions.

picotite. A dark-brown, translucent to almost opaque variety of spinel; a primary mineral in the kimberlite oc­currences of South Africa. At one time it was suggested as constituting many of the dark-appearing inclu­sions in diamond, but this was not confirmed by later research.

piedra del cabo. The Spanish term for South African diamond.

Piermatic Automatic diamond Polishing Machine. The Piermatic unit was invented by Mr. M.Liebowitz, a South African civil en­gineer, and developed by the Dia­mond Trading Company in the mid-1960's and early-1970's. It is limited to the cutting of round brilliant dia­monds. Reportedly, it is best suited for processing sawn crystals (four-point Diamonds) between 0.20 carats through 0.60 carats. The unit com­pletely polishes the pavilion facets, lower and upper girdle facets, and bezel facets. The star facets, table facet and culet (if any) must be polished by the traditional (non-automated) method. The newer Piermatic II is an improved Piermatic Machine.

pierres de fantasie. A French term meaning fancy-colored Diamonds.

piggy-back diamond. An "assembled stone" composed of a flat diamond with a large culet set above, but not touching, a smaller diamond result­ing in the appearance of a much larger stone when viewed from above.

 
Phoenix Mine phosphorescence photoluminescence Photostand PDF Print E-mail
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Sunday, 23 September 2007

Phoenix Mine. A small diamond pipe mine in the Winburg area, Orange Free State, Republic of South Africa.

phosphorescence (foss"-fo-ress'-cence). A variety of luminescence. The property possessed by some di­amonds and other Gemstones of con­tinuing to emit visible light in dark­ness after exposure to X-rays, cathode rays, ultraviolet rays or visi­ble light. It differs from fluorescence, which is an emission of visible light during exposure. Phosphorescence is a continuance of luminescence after the removal of the exciting rays, and a phosphorescent stone or other ob­ject is said to phosphoresce, or glow. Phosphorescent Diamonds are un­usual. See FLUORESCENCE, FLUOROCHROMA-TIC, LUMINESCENCE, PHOTOLUMINESCENCE, PRE­MIER diamond, ULTRAVIOLET, ULTRAVIOLET LAMP. CHAMELEON diamond.

photoluminescence (fo'-toe-loo'-ma-ness"-cence). The property of some Diamonds and other Gemstones to become luminescent when ex­posed to the action of visible or ul­traviolet light rays only. They are said to be fluorescent if luminescent dur­ing exposure, and phosphorescent if luminescent after exposure. See emis­sion SPECTRUM, FLUORESCENCE, LUMINESCENCE, PHOSPHORESCENCE, PREMIER diamond, UL­TRAVIOLET

Photostand. The GEM Photostand is an especially designed system for photographing jewelry. The unit con­sists of a Polaroid Automatic Land Camera with cable release, auxiliary Vi size, actual size, and \Vi size color-coded lenses and electric eye adaptor. The stand has a scientifically balanced color-corrected lighting system, with focusing and centeringndicators. It uses black and white or color film.

 
Peruzzi cut phenomenal diamond Pesas diamond Philip II Diamond PDF Print E-mail
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Sunday, 23 September 2007

Peruzzi cut. See peruzzi, vincenzio. Peruzzi, Vincenzio. A 17th century Venetian lapidary who is credited with first revealing the true beauty of the diamond by employing the bril­liant form of cutting; i.e., with 56 facets, a table and a culet. Some­times referred to as the Peruzzi cut, it was an improvement over the earlier Mazarin cut.

Pesas diamond. A misnomer for rock crystal.

phenomenal diamond. A general term for any diamond that displays an unusual optical effect. See

FLUORESCENCE, PHOSPHORESCENCE, FLUORO-CHROMATIC, TRANSICHROMATIC, PREMIER DIA­MOND.

Phianite. Trade name for man-made cubic zirconia.

Philip II diamond. A 47.50-carat diamond, supposedly purchased by Philip II, of Spain, in 1559. Further details lacking.

philosopher's stone. An imaginary stone, the use of which medieval al­chemists believed would transform flint into gold or into diamond and other precious stones.

 
pear-shaped rose cut pectolite penetration twin PDF Print E-mail
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Sunday, 23 September 2007

pear-shaped rose cut. A rarely used rose style of cutting that has a pear-shaped girdle outline, a flat, unfa-ceted base and a pointed, dome-shaped crown bearing 24 triangular facets; the number of facets, how­ever, may vary. Pecos diamond. A misnomer for rock


crystal from the Pecos River, Texas, or New Mexico.

pectolite. A subtranslucent, whitish or grayish secondary mineral found in the Kimberley diamond pipes; sometimes deposited in fissures of deep fractures in the surface of dia­mond crystals.

Pelikanstraat. The famous street in Antwerp, Belgium, about which the diamond-cutting industry centers. pendant-cut brilliant. The anglicized name for a pendeloque. pendeloque (pahn"-dah-loke). A modification of the pear-shaped bril­liant cut. It has an outline similar to the pear shape, but with the nar­rower end longer and more pointed.

penetration twin. A twin crystal in which the two or more parts appear to interpenetrate one another. The parts have some definite angular re­lationship to one another with respect to the axis of twinning. Pene­tration twins of cubes, tetrahedra and other forms are sometimes encoun-lered in diamond.
 
Paphos diamond Parisian diamond SYNTHETIC DIAMOND Parteal Mines PDF Print E-mail
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Sunday, 23 September 2007

Paphos diamond. A misnomer for rock crystal.

Para. A minor diamond-producing state in Brazil. See brazil.

Paphos diamond. (1) A term that seems to have been used first in the 16th cen­tury for Diamonds weighing mine than 12 carats. (2) A term once used by jewelers to mean "Diamonds free from specks or foulness." (3) A per feet diamond weighing 100 carats or more.

Paphos diamond. A collection made up ol clearly defined groups of Diamonds, which, after evaluation, is ready for sale. See lot and sights.

Parisian diamond. An old misnomer for a diamond imitation. Parsons, Hon. Sir Charles Algernon (1854-1931). An English engineer m\<\ inventor who, in 1918, attempted lo produce synthetic Diamonds by re peating the experiments of Moissan and Crookes with variations, and was convinced that these methods could not be successful. In one novel experiment he fired a blank shotgun shell against the piston of a compres sion chamber that was filled wilh carbon. When this was unsuccessful he sought still higher pressures by discharging bullets into a tapered carbon-filled hole in a steel block. Pressures of 5000 tons per square inch were supposedly obtained in this manner. There is no proof that his experiments were successful, See

SYNTHETIC diamond; MOISSAN, FERDINAND FREDERIC HENRI; CROOKES, SIR WILLIAM,

Parteal (or Partial) Mines. A group ol old diamond mines near Golconda, India, some of which were worked as late as 1850. Located on the north bank of the Kistna River, east ol the Kollur Mines, and at the junction ol the Kistna and Munyero Rivers. Said to have had large production from an alluvium of a decomposed cli.nnan tiferous stratum. See col< onda, itvii >i-v

 
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