SEEDS FROM THE CAROB
The final C is carat weight. What carat? The original "carats" were the seeds of a tree; on that, most authorities agree. But they disagree on the type of tree, where it grows and the size of its seeds. The best guess is that the first carats were seeds from the Carob tree, or Ceratonia siliqua, which is native to the Mediterranean and Near Eastern countries. Their nearly uniform weight led to their use for weighing pearls, gold and diamonds in ancient days. To be more practical, the modern carat equals 1/142nd of an avoirdupois ounce or, in metric terms, one fifth of a gram (200 milligrams). Each carat is divided into 100 points. Thus a diamond is described as weighing 1.32 carats-or one carat and 32 points.

THE DAY MR. ASSCHER FAINTED
How do you cut a very large piece of rough diamond? Very carefully.

But the planning of the cutting is much more exacting than the cutting itself. It can take months of study to decide just how to strike the first blow; the goal is to have the diamond break into manageable pieces. The horrible alternative is that the crystal may shatter. The cutter who handles the biggest pieces of rough, and they are very few and far between, is under immense pressure. The head of the Asscher Diamond Co. of Amsterdam, who was assigned the awesome task of cutting the world's largest known diamond, the 3601-carat Cullinan, had a doctor stand by when he hit the critical blow. His first attempt failed; reportedly he fainted after his second, successful, blow.

Diamond cutting in New York won international respect in 1936 when Lazare Kaplan, a legendary figure in the U.S. industry, cut the 726-carat Jonker Diamond. He devoted almost an entire year to studying the stone, making models in both plaster and lead. Kaplan and a number of veteran European cutters disagreed on the direction of the Jonker's grain; if Kaplan were wrong he would shatter the stone and send half a million 1936 dollars down the drain. On April 27 of that year he made his final decision, struck the cleaving knife and the Jonker "fell apart in my hand exactly as planned."

In recent times, what was first called the Zale diamond, an 890.25 golden-yellow stone, was unveiled to the public in New York in November 1984. But it was not until 1988 that Marvin Samuels and Louis Glick, who by then owned the gem, were ready to bring to market the final product -a 407.48 carat diamond called The Incomparable. Incomparable it may be, but when it went to auction in October 1988 the owner withdrew it when the top bid it attracted was $12 million.

The Cullinan is the greatest diamond of all time. It was found late one afternoon in 1905 by the superintendent of South Africa's Premier mine.

In 1907, the Cullinan was sold to the Transvaal Government, which presented it to Britain's King Edward VII.