polished goods polished rough polisher polishing mark
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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.