The Diamond Industry

The De Beers Central Selling Organization controls most of the world's supply of uncut diamonds through an international marketing cartel. Most of the world's producers of diamonds belong to the cartel to help maintain a high price for diamonds. De Beers companies have controlled the supply of diamonds since the late 1880's. Major centers for the cutting and selling of diamonds include New York City; Amsterdam, Netherlands; Antwerp, Belgium; Tel Aviv, Israel; and several cities in India.

The cutting and polishing of diamonds is called dressing. One of two processes is used: sawing or cleaving. Most diamonds are sawed. The rough stone is cut to a desired shape by a very thin, rapidly revolving disc the edges of which are embedded with diamond dust mixed with olive oil. In cleaving, a steel blade is placed against a natural groove in the diamond and struck a hard, sharp blow. The stone cracks along the line of the groove, much as wood will crack along the line of its grain. The faces of the split stone are then polished by whirling steel discs coated with diamond dust and olive oil.

Diamonds may be sawed or cleaved into many different shapes. The top of the diamond usually forms a fairly large flat surface, but the sides and bottom are generally cut into dozens of small, flat surfaces called facets. Light entering through one facet is reflected out through another. The refracting quality of the gem makes the light scatter, causing the diamond to give off a sparkling, many-colored light. This effect is increased by increasing the number of facets.

The value of a gem diamond depends upon its weight, the way in which it is cut, its color, and its purity. A pure diamond is one without flaws—that is, without cracks, pores, or deposits of either foreign material or uncrystallized carbon.