1n 1931, The GIA or Gemological Institute of America established a grading system known as the 4 C's that made the diamond pricing and grading possible. It then became the worldwide standard when the diamond industry quickly embraced this grading scale. Although there are several different grading systems used in other countries, the more globally accepted standard is the GIA's scale.

The 4 C’s refer to the Cut, Carat weight, Color, and Clarity of the diamond. Here’s a brief description of each:

Cut

The term cut generally refers to the shape of the diamond. Diamonds vary in shapes as illustrated below for your reference. Today, the term cut has evolved from referring merely to the shape of the precious stone to how well the diamond is actually cut. So, a round diamond is now evaluated in terms of being perfectly round or somewhat off-round. Based on the cut grading scale developed by the GIA, the overall cutting workmanship of a diamond is rated as Excellent, Very Good, Good, Fair or Poor.

Carat Weight

The term carat is used to refer to the actual weight of the diamond which is believed to have been derived from the word "carob". Carob is a kind of dry fruit that contains seeds. Back in the days, the carob seeds were commonly-known and understood by everyone so the diamonds and other precious gems were measured relative to the equivalent weight of the carob seeds.

A carat is technically equal to .20 grams, therefore, 5 carats weigh about one gram. For an example of the diameter of a round-shaped diamond in relation to its weight, please refer to the visual depiction below.

Color

The term color, for a diamond, applies to their perceived color or absence thereof. For a better understanding of the color grading scale, please refer to the illustration below. Commonly, diamonds display a more apparent tint of yellow and those are typically inexpensive. The extremely rare diamonds are those with very obvious yellow tint considered as fancy color which are usually the rarest and most expensive.

Clarity

Some diamonds have internal and external imperfections while others appear flawless. The measurement of diamond imperfections or lack thereof using the 10 power magnification is known as clarity. The more rare diamonds are those with less imperfections and are valued more expensively. The flawless diamonds are extremely rare and, therefore, has very expensive value.

Nothing is perfect and diamonds are no exceptions. Most diamonds in the market today have flaws that are visible to the eye. Scientists, however, have developed a process known as clarity enhancing to make those imperfections invisible. A material that closely resembles and with the same characteristics as diamond is filled into the imperfections or impurities using a high tech system. The result of the process is a diamond that naturally looks brilliant and very appealing to the eye that is almost half the price of the original diamond. Though they went through an enhancing process, these enhanced diamonds are still considered 100% natural diamonds.