Diamond Introduction
Brief Diamond History
The earliest sources of gem diamonds were India and Borneo, where they were found in river alluvium. All famous diamonds of antiquity were Indian diamonds, including the Great Mogul, the Orlov, the Koh-i-noor, and the Regent or Pitt. Other famous diamonds are the Hope (blue), Dresden (green), and Tiffany (yellow). In the early 18th cent., deposits similar to those in India were found in Brazil, mainly of carbonados, though they may have been known as early as 1670.
In 1867, a stone found in South Africa was recognized as a diamond. Within a few years, this began a wild search for diamonds, both in river diggings and inland. In 1870-71, dry diggings, including most of the celebrated mines, were discovered. Well-known South African diamond mines are the Dutoitspan, Bultfontein, De Beers, Kimberley, Jagersfontein, and Premier. Botswana, Namibia, and South Africa are now the world's major diamond-producing nations; other important countries include Australia, Russia, Brazil, Angola, Canada, Sierra Leone, Ghana, Tanzania, and Venezuela. The use of diamonds to finance African rebel groups and fuel civil strife in the 1990s led, in 2001 and 2002, to international agreements (the Kimberly Process) designed to certify legitimately mined diamonds.
A Diamond's Journey
The diamond has always exercised an irresistibly seductive power and an almost mythical fame. It is the most expensive of gems and the hardest of all minerals while exhibiting incomparable brilliance and scintillation.
Diamonds consist of pure carbon that crystallizes under very high pressure and temperature. Such and environment exists only at depths of 150 to 200 kilometers. From here diamonds make their long journey "housed" in the volcanic stone known as Kimberlite or "blue ground". Many volcanoes have eroded in the course of the centuries causing the diamonds to be released from this Kimberlite. They are then washed away and carried to river beds that then transport them to the many places where diamonds are ultimately found. Other volcanoes still have kimberlite pipes, which are mined directly. It is estimated that the kimberlite found in Africa and South America was created between 70 and 150 million years ago.
In its unpolished form, a diamond is a rather vague crystal form, without any real luster. Only a succession of processes brings out their undisputed beauty. Each diamond is unique and must be studied in detail to determine the most advantageous manner to work it with the least loss of weight and the greatest clarity. With a pen and India ink, the direction in which the diamond must be cleaved or sawn is indicated. The cleaving is done to split one stone into two or more or to remove impurities. Imagine the process of splitting wood. Cleaving is done parallel with the grain of the crystal while sawing is done against the grain. Sawing is accomplished with a very thin blade that rotates at a very high speed (15,000 rpm) and is coated with diamond powder mixed with oil. The second step in the process is girdling. This is rounding the base of the sawn or cleaved piece so that it more or less resembles a polished diamond. Finally the diamond is faceted on a polishing wheel. This machine consists of a horizontal, circular cast-iron disc that is, of course, charged with diamond dust. The cut of a diamond is perhaps man's only contribution to a diamonds beauty. The cutting process unleashes the hidden fire and brilliance from an otherwise unattractive rough crystal.