Diamond is a pure or nearly pure form of crystallised carbon of extreme hardness and valued as a precious stone. The most familiar usage of diamonds today is as gemstones used for adornment. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching perhaps contributing to its popularity as the preferred gem in an engagement ring or wedding ring, which are often worn every day.

If you plan on obtaining a diamond because you like how it looks or if gives you or your love one pleasure then the price of a diamond may be well worth its purchase. However it is also well worth your while to ensure that you get it properly certified. Such a valuation will typically take into account the four basis qualities of a diamond know as the four Cs.

Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat, cut, color, and clarity. Diamond prices (particularly among wholesalers and other industry professionals) are often quoted per carat, rather than per standard weight. A carat is a measure of weight used for gemstones, and is equal to 200 milligrams. Weights are given to the nearest 1/100th of a carat, an amount that is called a "point." For example, a .50 carat gemstone might also be called one-half carat or a 50-point stone. The carats of a diamond are taken seriously in providing certification for the value of a diamond.

All diamonds are compared against to an internationally accepted set of master stones and ranges from totally colorless (D) to pale yellow or brown color (Z). Color grades D through F are naturally the most valuable and expensive because of their rarity. Brown diamonds darker than K color are usually described using their letter grade, and a descriptive phrase, for example M Faint Brown. Oddly enough, diamonds graded Z is also rare, and the bright yellow color is also highly valued.

Diamonds become increasingly rare when considering higher clarity grading. Clarity is a measure of the number and extent of the flaws in the diamond. The setting diamonds are placed in also affect the performance of light through a diamond. Clarity is determined by the number of blemishes on the surfaces of the diamond and the number of inclusions such as air bubbles, cracks, and foreign material inside of the diamond.

Today, because of the relative importance of carat weight in society, many diamonds are often intentionally cut poorly to increase carat weight. If any of these cutting factors are below standard then the appearance of the diamond will be adversely affected. The cut of a diamond describes the quality of workmanship and the angles to which a diamond is cut. Popular fancy cuts include the baguette (from the French, meaning rod or loaf of bread), marquise, princess cut (square outline), heart, briolette (a form of the rose cut), and pear cuts. These newly developed cuts are viewed by many as more of an attempt at brand differentiation by diamond sellers, than actual improvements to the state of the art.

When providing certification a jeweller will take all of these factors into account. The four Cs of diamonds carat, color, clarity and cut are vital in identifying the value of a diamond and will ensure that a buyer of diamonds has purchased a quality product.