This great article I found on http://www.firenzejewels.com/
Buying a diamond signifies an important moment in your life, and we understand that for many it can also be a bit of an intimidating experience. For most people, buying an engagement ring is the first, most important purchase to date. For your convenience, we have gathered some of the basic, general concepts (a.k.a. the 4 C’s) that you should become familiar with as you start looking for a diamond…
CLARITY
Diamonds have unique birthmarks or natural inclusions (found internally, though some may break the surface of the stone), and blemishes which include scratches and nicks on the diamond’s surface. Clarity refers to the relative absence of inclusions and blemishes. A diamond’s clarity is determined by using a 10X magnifying glass and a trained eye.
Below is a list of the clarity grades. Moving from one grade to the next can greatly influence the overall value of a diamond. Diamonds that have fewer inclusions are rarer, and therefore more valuable.
COLOR
Normal color range diamonds (what most people consider ‘white’ diamonds) are graded by their relative lack of color. A diamond that is ‘whiter’ has little or no visible coloration. Diamonds with less color are considered more desirable and have a higher value.
Below is a chart illustrating how diamonds are graded according to color by the Gemological Institute of America (GIA).The difference in color between one letter grade to the next is quite small. It usually takes a well trained eye and years of experience to color grade a diamond.
Truly colorless diamonds are actually quite rare. Most diamonds used in jewelry are nearly colorless, and fall in the normal color range.
It is important to distinguish the normal range ‘white’ diamonds from ‘fancy’ color diamonds. Diamonds actually range in color from faint yellow or brown to very rare pinks, blues, greens, and other colors known as “fancies”.
CARAT WEIGHT
Diamonds are weighed in units of a metric carat (ct). One metric carat is just over .007 ounce. One ounce is equal to almost 142 carats. When a diamond weighs over a carat, the weight is expressed in carats and decimals, rounded to the nearest hundredth of a point (i.e. 1.52 ct).
One important point to keep in mind when considering the carat weight of a diamond is to know that the ‘per carat’ price increase significantly as a diamond gets larger. For example, we know that all things held equal (same cut, color, clarity) larger stones are worth more than smaller ones. However, many people don’t realize that a 2.00 carat diamond is worth more than just twice as much as a 1.00 carat diamond. This is because larger diamonds are rarer than smaller diamonds. The more scarce the diamond is, the more it is worth.
Carat weight is an obvious factor in determining the value of a diamond. However, two diamonds of equal carat weight can have very different prices, depending on their quality.
CUT
Many people confuse cut with the shape (i.e. round, princess, oval) of a diamond. The shape of the diamond is mainly a matter of personal preference and does not directly affect the value. Cut refers to the proportions and finish of a diamond. Cut is what enables a diamond to make the best use of light. It is the work of a master cutter that allows the diamond to be cut in such a way as to permit the maximum amount of light to be reflected through the diamond.