Buying Diamonds - Four Cs
Four factors, known as the “Four C’s,” determine the value of a diamond.
Clarity: A diamond’s clarity is affected by any external irregularities or internal imperfections created by nature. Clarity characteristics are classified as inclusions (internal) or blemishes (external). The size, number, position, nature, and color or relief of characteristics determine the clarity grade. Very few diamonds are flawless, that is, show no inclusions or blemishes when examined by a skilled grader under 10x magnification. If other factors are equal, flawless stones are most valuable. A stone’s grading is dependent on its relative position on a flawless-to- imperfect scale.
Color: Diamonds come in every color, but the most popular is colorless. Grading color in the normal range involves deciding how closely a stone’s body color approaches colorlessness. Most diamonds have at least a trace of yellow or brown body color. With the exception of some natural fancy colors, such as blue, pink, purple, or red, the colorless grade is the most valuable. Colorless diamonds are graded D, and the grading continues down through the alphabet, with each letter designating a slightly yellower tint
Cut: The proportions and finish of a polished diamond (also called make). Each diamond is cut according to an exact mathematical formula. The most common cut, the round brilliant, has 58 facets or small, flat, polished planes designed to yield the maximum amount of light reflected back. This reflection is known as “brilliance” and is an important factor in evaluating a diamond. The finish includes polish and details of facet shape and placements. The cut affects both the weight yield from rough and the optical efficiency of the polished stone; the more successful the cutter is in balancing these considerations, the more valuable the stone will be. The cut can also mean shape, as in an emerald cut or marquise cut.
Carat Weight: The weight of a diamond is measured in carats. There are 142 carats to an ounce. Carats are further divided into 100 points. If other factors are equal, the more a stone weighs, the more valuable it will be.
Flawless diamonds show no blemishes or inclusions when examined by a skilled grader under 10x magnification.
The following do not disqualify a stone from the flawless category:
- An extra facet of the pavilion which cannot be seen face-up
- Naturals totally confined to the girdle, which neither thicken the girdle nor distort its outline.
- Internal graining which is not reflective, white, or colored, and does not significantly affect transparency.
Internally Flawless (IF)
IF stones show no inclusions and only insignificant blemishes under 10x magnification. Normally what separates IF from FI stones are characteristics that can be removed by minor repolishing (light surface graining is an exception).
Very Very Slightly Included (VVS1, and VVS2)
VVS diamonds contain minute inclusions that are difficult for even a skilled grader to locate under 10x. in VVS1, they are extremely difficult to see, visible only from the pavilion, or small and shallow enough to be removed by minor repolishing. In VVS2, they are very difficult to see.
Very Slightly Included (VS1 and VS2)
VS stones contain minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) for a trained grader to see under 10x. Small included crystals, small feathers, and distinct clouds are typical.
Slightly Included (SI1 and SI2)
SI stones contain noticeable inclusions, which are easy (SI1) or very easy (SI2) to see under 10x. In some SIs, inclusions can be seen with the unaided eye.
Imperfect (I1, I2, and I3)
I-graded diamonds contain inclusions which are obvious to a trained grader under 10x magnification, can often be easily seen face up with the unaided eye, seriously affect the stone’s potential durability, or are so numerous they affect transparency and brilliance.