For centuries, cultures have regarded diamonds as beautiful, magical, mysterious, and powerful. These precious stones have been sought after, fought over, and worshiped. Diamonds are associated with wealth, achievement, status, and love. The meaning and rarity of diamonds brings about much to consider when making a purchase. The rough gemstones must first be mined and cut. Once cut, diamonds are appraised to determine their value. Some of them undergo treatments to augment their appearance. Diamonds progress through these processes to be transformed into beautiful valuable pieces of personal adornment.
Diamond is a crystallized form of carbon that grows deep in the earth, under immense pressure and heat. This form of carbon crystal is the hardest natural substance known to humans. Diamonds are brought to the surface by volcanic eruption. These types of eruptions are referred to as pipe mines because they resemble pipes in the ground with molten minerals moving through them. The pipe's surface layer is a clay-like rock known as yellow ground for its color. Under the yellow ground is a layer of a mineral referred to as kimberlite. Both layers serve as matrices for diamonds. This mining process originated in India over 4,000 years ago, and the modern mining industry began with discoveries in South Africa in the late 19th century. Today, the top seven diamond producing countries, accounting for 80 percent of the world's rough diamond supply, are Botswana, Russia, South Africa, Angola, Namibia, Australia and Zaire. (Levinson 234)
A good deal of technology is used in mining diamonds. The matrix is removed by blasting and by automatic block carving machines. The rock is first broken up into smaller pieces, then the waste is removed, and the concentrate with the gemstones is left behind. The extraction of the diamond from the concentrate was formerly done by hand. Extraction from the matrix is now done by putting the concentrate on a vibrating belt greased with fatty substances that are adhesive to diamonds. Further separation is done by optical selection with the use of photocells and x-ray technologies. On average one ton of diamond ore yields half a carat of diamond (one or more diamonds adding up to less than the volume of a pencil eraser). (Levinson 246)
Once the rough gemstones are extracted, they must be evaluated. The evaluation determines whether the diamonds are worth cutting for use in jewelry. Only about 20 percent of diamonds mined are used for adornment purposes. The rest of them are ground up and used for grinding wheels, glasscutters, milling cutters, and scientific purposes. The diamonds that are worth cutting are cut in a myriad of styles and shapes. The brilliant cut is the most common, as shown in figure one.
Fig. 1. Brilliant cut diamond and ideal proportions; rpt. in GIA.
There are several steps to cutting and...