Diamond Lessons

The term "carat" goes back to the traders of the ancient world. A standard weight was required for precious gems as merchants of the ancient Mediterranean and Middle East were dependent on the ability to trade with a reasonably consistent unit of measurement. It was this need that lead to the adoption of seeds and grains as widespread accepted units of measurement.

The carob seed and the wheat grain, both of which had been used for food purposes, were found to be ideal units of weight. This was a result of the fact that any given carob seed weighs, for all practical purposes, the same as any other given carob seed. In addition, any given grain of wheat has an identical weight to any other grain of wheat. In time, the carob seed became the standard unit of weight for gems. The word carob itself comes from the Arabic word for the carob seed, the quirat. Through the rise and fall of civilizations, this word became corrupted through to the Greek, keration, which eventually became what we know today as the carat.

For centuries the carob seed remained the weight measurement for precious gems. By the middle ages, however, changes in trade routes had occurred, and large centers of trade were now found within Europe. The carat, as it had become known, became linked to 4 grains Troy weight, with the carob seed having been abandoned at some point during the shift of trade centers. The Troy carat was the equivalent of approximately 205 milligrams. This measurement of weight lasted for the carat until the 20th century. It was between 1907-1914 that the carat was married to the metric system of weights. By 1914 the United States officially abandoned the former Troy measurement of 205.3 milligrams for the carat, and adopted the current metric carat measurement of 200 milligrams.

The different diamond cuts were developed over the centuries, in order to utilize the most raw diamond and extract the best possible finished diamond. By the turn of the 20th century, mathematical principles were put to use to create theoretical models for developing the ideal models for diamond cuts. It was out of this atmosphere that Marcel Tolkowsky, in 1919, developed the first mathematical guideline for the ideal proportions for a round diamond, in order to achieve the greatest level of brilliance. However, Tolkowsky' s ideal is not the only measure of proportions for diamond cut in use today. The Tolkowsky ideal, or American Standard, is the primary set of proportions in use for measuring an ideal diamond cut in North America. However, each of the other shape of diamond has a guide for the "preferred" proportions and should not be held to the same percentages as ideal rounds.

A diamond is usually cut into one of three basic shapes: brilliant, step and mixed.

Brilliant cut

This is by far the most popular of current cuts. The brilliant cut is characterized by its use of kite-like or triangular facets, angled so as to best create the brilliance and luster of diamond. The round brilliant--with 57 facets (not including the culet), 33 on the crown (above the girdle) and 24 on the pavilion (below the girdle)--and the princess cut are prime examples of the brilliant cut diamond.

Step cut

The step cut is characterized by long, rectangular facets, which run parallel to the girdle, as opposed to the brilliant cut, in which the facets face away, up or down, from the girdle. The emerald cut and Asscher cuts are good examples of the step cut diamonds.

Mixed cut

As the name implies, the mixed cut blends aspects of both the brilliant cut and the step cut. This means that the cut can have both triangular and kite-like facets next to broad, rectangular plane-like facets. This is a cut that is often utilized in colored diamonds, as well as, exclusive trademarked cuts.

One of the primary reasons for the creation of so-called "Fancy Cuts" can be found in the fact that prior to the development of the round brilliant cut, diamond cutters would cut diamonds based on the shape of the raw diamond. While cutters still follow this guideline, the round brilliant cut has brought about more raw diamonds being cut down to the round brilliant as it the most desired shape in the market today.

An experienced cutter could see what type of shapes would best optimize the weight from the raw diamond, and would cut the diamond according to the raw diamond's characteristics. Lighting, be it by natural, candle or gas lighting of later centuries, is also considered by the diamonds cutter.

There are many reasons for fancy cuts, from the practical to the fashionable. Fancy cuts also tend to be broken up into four categories: modified brilliants, step cuts, mixed cuts, and rose cuts.

Modified Brilliants: Modified brilliants are, as the name implies, brilliant cut diamonds with shapes modified from the standard round brilliant. There are numerous shapes that modern technology and cutting mechanics can allow for, including the heart, marquise, trillian and navette. The modified brilliant cut is popular, as it gives the brilliance of the round brilliant cut, but in more unique and personalized shapes. The problem occurs in that modified brilliants are also prone to greater threat of damage, as the irregular shapes resulting from such cuts offer a fragility of form that can easily chip or fracture, and so additional precautions must be taken.

Step Cuts: Also known as trap cut, this cut is characterized by a rectangular or square shape, with the facets of the crown and pavilion running parallel to the girdle, and is one of the oldest forms of cut. The advantage of the step cut is that it preserves more of the weight of the raw diamond than the brilliant cut. One of the most popular examples of the step cut is the emerald cut. The emerald cut has the long faceted planes of the step cut, but has cut corners, which helps to avoid chipping or cleaving of the edges. The culet is not present in step cut stones, but rather they have a keel that extends along the length of the end or bottom of the pavilion. Step cut stones do not have the fire or flash of brilliant cut diamonds, but do exhibit brilliance and scintillation as the light moves clearly between the mirror-like facets. Due to the nature of the long facets, step cut stones must have tremendous clarity, as any flaws can be easily noticed. This means that step cuts have a high luster, and a warm glow. Triangle, obus and kite cuts are also included in the step cut category.

Mixed cuts: The mixed cut is the melding of both brilliant cuts and step cuts. The intended effect is to offer the brilliant finish of the brilliant cut, while preserving the weight retention of the step cuts. This effect is achieved through cutting the facets on the crown (or the part of the diamond above the girdle) in the step cut fashion, with the facets cut long and running parallel to the girdle, and with the facets on the pavilion (or the part of the diamond below the girdle) cut like the brilliant cuts. Mixed cuts are newer in the world of diamond cuts, with the first mixed cuts dating back to as recently as the 1960s. The extremely popular Princess cut is the most well known of the mixed cuts, and has grown popular enough to warrant its own grading system with most gemological laboratories.

Rose cut: These are, like the step cuts, an older cut of diamond. Developed prior to the use of electric lighting, rose cuts fell out of favor in the early 20th century, due to their lack of brilliance. Characterized by a lack of a pavilion, the crown rises from its base, with 12 or 24 triangular facets, reaching up to form a point. They are seeing a renewed rise in popularity as the market for older, antique jewelry makes the use of the rounded rose cut type stones more desirable.

Diamonds were first discovered in alluvial deposits in southern India about the 9th century BCE, and for centuries India remained the world's primary source of diamonds. This changed in the 18th century with the discovery of large diamond deposits in Brazil in 1725. Over a century later diamonds were discovered in South Africa, and so began the leadership of South Africa in the diamond trade.

Today diamond mines are found throughout the world. The current leading nations in diamond production are still found in Africa, but other nations are beginning to produce diamonds in the volume in which African nations have been operating for the past century and a half. Three of the world's leading diamond producing countries are in Africa: Botswana, Namibia and South Africa. The non-African leaders in diamond production include Canada, Brazil, Venezuela, Russia, and Australia.

Canadian diamonds gained a strong foothold in the diamond trade when the politics met up with geology. As large diamond deposits were found in the Canadian Northwest Territories in the 1990s it was concurrently discovered that the nations of Sierre Leone, Angola and The Republic of Congo were using their diamond sales to fund civil war. The branding of such diamonds as "conflict diamonds" gave the new Canadian mines the ethical upper-hand, and so helped to bring Canadian diamonds to the forefront of diamond production. The Canadian diamond mining industry has strict regulations in place, documenting all of the diamonds produced from their mines. In this way these diamonds are assured of being Canadian diamonds, including having a polar bear mark inscribed on the diamonds in order to brand them.

South America is also still producing diamonds in large quantities, almost 300 years since they were first discovered there by western interests. Brazil and Venezuela are the two major diamond producing nations in this area. Newly available technology has allowed more diamond deposits to be mapped, giving this area the ability to remain strong in diamond production.

The world leader of diamond production is still South Africa. For the past century and a half, South Africa has been the world leader in producing and transporting diamonds. It is through South Africa's mass production, distribution and shrewd business decisions that they remain the world's diamond leader. It is in South Africa that the diamond industry's leader, DeBeers is located. Through their ownership of the primary and largest diamond mines in the world, DeBeers is able to control much of the diamond industry. However, diamond deposits in Russia's Siberia region and the newly discovered deposits in Australia's Northern and Western Territories are closing the historic diamond production gap.