river bort River of Light Diamond
Written by Administrator   
Monday, 29 October 2007

river bort. Poor-quality alluvial dia­mond.

river diggings. diamond-mining op­erations in gravels along river val­leys. See ALLUVIAL DEPOSITS, ALLUVIAL SORT­ING, GEM GRAVEL, WET DIGGINGS, POTHOLE,

River of Light diamond. See darya-i-

NUR diamond.

River Styx diamond. A coarse and knotty black crystal. Found in the Bultfontein Mine, Republic of South Africa. Purchased from a European dealer by Jack M. Werst, Miami, Florida, gem dealer, and cut to a 28.50-carat brilliant and a 7-carat marquise. The cleaving and polishing, done by a New York City dia­mond cutter, Maurice Italiaander, re­quired several months because of the knots. In 1958, stolen in an armed robbery and never recovered. river-to-light-yellow system. A widely used color-grading system for the most commonly encountered color range of Diamonds; i.e., the colorless-to-yellow range. The usual grades include river, top Wesselton, Wesselton, top crystal, crystal, top cape (or silver cape), cape, dark (or low) cape, very light yellow, light yellow and yellow. For a comparison of this system to those used by the Gemological Institute of America and the American Gem Society, refer to chart in Appendix entitled, Com­parison of Several Different diamond Color-Grading Systems. See also cia


Riverview. A minor alluvial diamond deposit in the Kimberley area, Cape Province, Republic of South Africa. The total yield from this digging dur­ing one recent year amounted to less than 300 carats.