Diamonds Introduction 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. Production Mining 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) Cutting 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 polishing a diamond. The laps (cutting wheels) used in the process are all coated with diamond because the only material hard enough to cut diamond is another diamond. First, the rough diamond is cleaved.
This means that the gemstone is sawn to prepare it for initial shaping. Once cleaved, the gem goes through the bruting process where it is given a shape with a girdle, crown, and pavilion. The final facets are then put on the gemstone and it is polished. The diamond is then ready for appraisal. (Levinson 238) Characteristics It is important to understand how the quality of a diamond is determined, and why some diamonds are more rare and valuable than others are.
Value depends on quality, and the quality of a diamond depends on four characteristics called the 4Cs: Cut, Color, Clarity, and Carat weight. (GIA) What do these terms mean when it comes to buying a diamond, and is one C more important than another is? To make it simple, the larger the diamond, the rarer it is (carat weight); the purer the diamond, the more valuable it is (clarity); the less color in a diamond, the more beautiful; and the more precise the cut of the diamond, the more brilliant it is. The combination of these individual factors makes up the diamond’s overall quality and determines its beauty. Cut Once the diamonds are cut, they must be appraised to determine their characteristics and value. Cut and shape are often confused. Shape is only part of the cut.
Shape is the form created by the stone when looking upon it from a top view. Common shapes for diamonds to be cut are round, pear, emerald, heart, oval, and marquise. These shapes are pictured in figure two. The shape of the diamond does not affect its value. Fig. 2.
Common shapes for cut diamonds; rpt. in GIA. Most round diamonds are cut to have 58 facets. It is the work of a master cutter that allows a diamond to be cut in such a way as to permit the maximum amount of light to be reflected through a diamond. This creates a good brilliance or sparkle.
(GIA) There are several cuts of diamonds. The one with the greatest value is the ideal cut. The ideal cut diamond describes a round brilliant diamond that has been cut to exact mathematically derived proportions. Its symmetry produces great luster and beauty. When a diamond is cut to the ideal proportions all of the light entering from the top of the gemstone in any direction is reflected back through the top and is dispersed into a display of colors.
The other cuts are deep and shallow cuts. In the deep cut light is lost through the sides of the diamond because the diamond is too deep, the result is a dark spot in the center. A shallow cut loses light through the bottom of the gemstone because it is too flat; the result is a gray ring inside the table edge. (GIA) These diamond cuts are illustrated in figure three. Ideal Deep Shallow Fig. 3.
The different proportions of cut diamonds and their light refraction; rpt. in AGS. The American Gem Society (AGS) was the first national organization to develop and use a system for determining how well a diamond is cut based against the ideal proportions. The cut grade system uses a scale ranging from zero, being ideal, to ten, being poor. (AGS) Color Diamonds were fo …