Chemically, a diamond is one of the world's simplest gemstones, as it is composed of the single element carbon. When carbon is subjected to extreme heat and pressure, it forms an octahedron molecule that becomes translucent and colorless. A diamond is a mass of these crystallized carbon molecules. Most diamonds were formed by heat and pressure in the earth's core more than 70 million years ago and were brought to the surface by volcanic eruptions.
A chemically pure and structurally perfect natural diamond is truly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow or gray hue is detectable, while intense pink or blue diamonds (such as the Hope Diamond) can be dramatically more valuable.
AGS- The American Gem Society, founded by Robert M. Shipley in 1934, is a non-profit professional organization of jewelers in the US and Canada. Its goal is to encourage ethical practices, advance knowledge and improve and maintain the image of the jewelry industry. AGS maintains the AGS Labs to develop and promote acceptable standards for grading a diamond's cut.
Bezel setting - A setting technique, which the diamond is completely surrounded by metal.
Blemish - A flaw on the surface of a diamond, either found on the original rough or caused after the stone has been mined.
Brilliance - The brightness or reflective characteristics of a diamond. Brilliance is created when light enters the diamond at the top, bounces off the pavilion facets and is reflected through the table back to the viewer.
In the past if something looked like a natural diamond, it probably was a diamond. Today, technology exists to create, alter, or simulate a diamond. The potential for uncertainty is boundless. For that reason, descriptive words take on great importance and must be used accurately. The Federal Trade Commission addresses nomenclature in its Guide for the Jewelry, Precious Metals and Pewter Industries. Whether a diamond is natural, synthetic or imitation will have a bearing on its price. A natural diamond is more valuable than a synthetic with otherwise similar characteristics. A synthetic diamond will be more valuable than an imitation diamond. To create less confusion in the marketplace jewelers abide by the nomenclature put forth by the Federal Trade Commission.
Natural Diamonds
A diamond is the natural gem produced from carbon deep within the planet's lithosheric mantle over a period of millions of years. Diamonds are brought to the earth's upper crust by volcanic activity. The word diamond, alone, can only be used to describe a gemstone created by this natural process.
Treated diamonds are diamonds that have been manipulated in some way to enhance their beauty. Diamonds have been treated since the Victorian era. It is rarely evident to the naked eye when a diamond has been treated. Federal guidelines mandate the when the treatment is not permanent, require special care, or have significant effect on the value the treatment must be disclosed to the consumer.
A chemically pure and structurally perfect natural diamond is truly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow or gray hue is detectable, while intense pink or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. 
Treated diamonds are diamonds that have been manipulated in some way to enhance their beauty. Diamonds have been treated since the Victorian era. It is rarely evident to the naked eye when a diamond has been treated. Federal guidelines mandate the when the treatment is not permanent, require special care, or have significant effect on the value the treatment must be disclosed to the consumer.
