115 Monmouth Road
West Long Branch, New Jersey 07764

732-542-6200
1-800-625-8300
info@thejewelrybroker.com

Diamond Buying Guide

The 4 C's are the four variables that determine the value of a diamond. They are:

Carat Weight
Clarity
Color
Cut

Carat Weight

Carat weight is the standard of measurement for the gemstone industry. One carat equals .2 grams. (Historically, the "carob bean" was used as the standard , which although was not precise, had a fairly consistent weight. This is where the name "carat" came from.). For stones under one carat, carats are generally broken down into "points", where, 100 points equals one carat (ct). 50 points equals ½ CT, 25 points is ¼ CT, and so forth. An .86 CT diamond is said to be 86 points, or sometimes an "86 pointer".

Note that carat weight does not really mean size. Because carats are weight, the actual size of two diamonds having the same carat weight can vary, depending on the proportions (diameter, depth, length, width, etc.). In other words, two diamonds having the same carat weight, may appear to be different sizes if one is cut deeper or shallower than the other.

Clarity

Clarity is an evaluation of internal characteristics, judged under 10x magnification. The Gemological Institute of America (GIA) has developed the grading system which is the international standard. The grades range from "FLAWLESS' to "IMPERFECT".

One point to keep in mind is that stones with fewer or no inclusions are not necessarily "better", but rather are "rarer" in nature, and therefore more expensive.

By the GIA definition, any diamond graded SI2 or higher has no eye visible inclusions. Inclusions rarely, if ever, affect the "brilliance" or "fire" of a diamond. Light enters a diamond from so many directions, that the microscopic inclusions do not interfere.  Only major inclusions in an imperfect stone will reduce brilliance.

Color

Color grading is also standardized using the GIA color grading system. Color in a diamond is more accurately described as "lack of color". Most diamonds occur in nature having minute impurities causing them to have a slight yellowish cast. The more a diamond approaches absolutely colorless, the whiter it appears when cut. Colorless diamonds are quite rare in nature and are therefore the most expensive.  The GIA color scale begins with the letter D and ends with Z , for white stones (Fancy colored diamonds such as yellow, pink, blue, etc. are graded differently). This scale ranges from colorless to yellow.

Cut

Cut is probably the most important factor in achieving beauty and brilliance in a diamond, but is also the least understood and most vague when assigning value. Cut refers to two things: Shape and proportion.

The standard diamond shapes are:

Round
Oval
Pear
Marquise
Emerald cut
Heart shape
Princess
Radiant

Shape appeal is an entirely personal preference but be aware that shapes that are the most symmetrical are the most brilliant. Because round diamonds are the most brilliant, they are also the most popular. Due to the common principals of supply and demand, round diamonds are generally the most expensive shape.

Proportion is the single most important element in determining brilliance in a diamond. The angles of the diamonds facets are what causes light to reflect through the stone in a quality known as "Fire". Most diamonds are cut in a compromising way, so as to retain as much weight as possible from the rough crystal, yet achieve maximum brilliance. Only diamonds cut to "Ideal Proportions" truly achieve the maximum possible brilliance or fire. The Ideal Cut is a mathematical formula, developed in the 1920's, for cutting diamonds at the precise angles and proportions necessary for light to be reflected and exit through the top of the stone. In other words, there is no light leakage or "dead spots" when looking into the stone. Light rays from all sides of the diamond are bent towards the center of the stone and reflect back through the top in rainbow blaze of light! This can only really be achieved in round stones, which are absolutely symmetrical.

The reason all diamonds are not cut to this standard is because it requires losing extra weight from the rough crystal. Therefore, Ideal Cut diamonds are a premium cost, because one must pay for the "lost weight". The advantage is a more brilliant diamond!