The 4 C's of a Diamond
1. Carat Weight
Did you know that diamonds and other gemstones are weighed in metric carats? One carat equals 0.2 grams, about the same weight as a bobby pin. Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. Two diamonds of equal weight can have very different values depending on the other members of the Four C's, clarity, color and cut. It's important to note that a carat is not the same as karat, 22K gold, which is referring the gold purity.
Fun fact, the majority of diamonds used in fine jewelry weigh one carat or less.
When it comes to color, it's all about what you can't see in regards to diamonds. These gems are valued by how closely they approach colorlessness. Less color = higher value. (The exception to this rule are diamonds that are meant to be seen in shades of pinks and blues.)
According to the Gemological Institute Of America's (GIA) color-grading scale for diamonds, the industry standard, the scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown. Every letter grade has a defined range of color appearance.
Did you know that many of these color distinctions are so subtle as to be invisible to the untrained eye? But these slight differences make a big, dazzling difference in diamond quality and price.
Diamond clarity refers to the absence of inclusions and blemishes. These imperfections usually develop when the gems are first formed, deep within the earth under extreme heat and pressure. Diamonds without these birthmarks are rare and this impacts a diamond’s value. Having said that, every diamond is unique and none are absolutely perfect under 10× magnification.
Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless to diamonds with obvious inclusions. The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) - No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) - No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) - Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance
It may be easy to confuse shape and cut for a diamond, but they are not the same. The shape of a diamond refers to an outside line, like round, pear, or marquise. Cut refers to the balance of the facet arrangements. It is about how well or not well the light reflects back to your eye. Cut quality is the factor that fuels a diamond’s, sparkle and brilliance. This is one of the main factor's in a diamond's beauty.
The GIA Diamond Cut Grading System for standard round brilliants in the D-to-Z color range is based on the assessment of seven components. The first three — brightness (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved) — are appearance-based aspects. The remaining four — weight ratio, durability, polish, and symmetry — are related to a diamond's design and craftsmanship.
In GIA’s system, each component is assessed individually, taking into account the relative importance of that component in the overall cut quality of the diamond. Each cut grade, based on a relative scale from Excellent to Poor, represents a range of proportion sets and face-up appearances. There are many different proportion sets that produce attractive diamonds.