About 2,000 years ago, the only known diamonds were of Indian origin and were not cut or faceted. There are four gold rings each set with an uncut octahedral diamond crystal in known private collections. The Indian diamond crystal was cherished for its colorlessness, which allowed it to act as a prism splitting white light into prismatic colors. The earliest known important diamond dates from the 4th century A.D. The diamond originates from an Indian diamond mine and is mounted in a massive Roman gold ring with an opening at the bottom so the adamantine or "all-conquering" spirit of the diamond might flow into the wearer of the ring. In the early 15th century, diamond dust and a slow moving diamond wheel were developed to grind down one point of the diamond converting it to a perfect "table cut." A table cut diamond ring from Antwerp dated at 1620 shows the increase in brightness achieved by the European cutters. Similarly, when the rose cut was perfected in the early 17th century, the observed fire in a diamond was greatly enhanced. In the late 17th century, various cutting centers developed in London, Antwerp, Paris, and Amsterdam. Uncut diamonds were shipped by Elihu Yale and other diamond traders from Madras to European cutters. The European brilliant cut, often with high crown angles much like the Indian cut diamonds, as well as a more symmetrical pavilion faceting plan, greatly increased the brightness and fire of the diamond. Jean Baptiste Tavernier, a knowledgeable European traveler to India, noted that Indian diamond cutters placed a great many facets on a diamond primarily to hide inclusions. The open Indian culets have long been regarded as "weight savers." In fact, this style actually increased diamond brightness. Marcel Tolkowsky's proportions, designed to maximize brightness, may create a diamond with less "charm" or "character" than the earlier cuts. Recent GIA cutting standards, using engineering and scientific solutions, try to bridge the lessons learned centuries ago in India and in Europe with today's desire for diamonds that have high brightness and a large amount of fire. [ABSTRACT FROM AUTHOR]