What are the 4 C’s of diamonds?
A diamond’s quality is determined by the 4C’s. The grades a diamond carries in these four areas give a clear idea of the diamond’s quality, and by extension the right price you should be willing to pay.
Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light.
An excellent cut diamond has a maximum amount of scintillation, brilliance and fire. Light enters the diamond and refracts back out with very little light lost. This exceptional grade represents roughly the top 3% of diamonds.
A diamond with a very good cut grade will reflect most of the light and will appear somewhat similar to an ideal cut diamond. This diamond will have superior sparkle, brilliance and fire.
Reflecting most of the light entering the diamond, this diamond cut has above average beauty. Diamonds with this grade won’t have as much brilliance and fire as higher cuts.
Diamonds graded fair don’t have the optimum brilliance and fire, as they allow a significant amount of the entering light to exit on the bottom or side of the diamond instead of through the top. These are still quality, but not nearly as well performing as a finer cut.
Diamonds with a poor cut may appear dull because the majority of the light is lost through the bottom or sides of the diamond. With a noticeable decrease in sparkle, even an untrained eye can see a sharp difference between this and higher cuts.
Diamond Color is graded in terms of how white or colorless a diamond is. The GIA grades diamonds from D to Z, with D being the most colorless, and Z containing noticeable brown or yellow tint.
While there are differences in color between D, E, and F diamonds, they can be detected only by a gemologist in side by side comparisons, and rarely by an untrained eye. D-F diamonds should only be set in white gold / platinum. Yellow gold reflects color, negating the diamond's colorless effect.
While containing traces of color, G-J diamonds are suitable for a platinum or white gold setting, which would normally betray any hint of color in a diamond. Because I-J diamonds are more common than the higher grades, they tend to be a great value. An I-J diamond may retail for half the price of a D diamond. Within the G-J range, price tends to increase 10-20% between each diamond grade.
Beginning with K diamonds, color (usually a yellow tint) is more easily detected by the naked eye. Set in yellow gold, these warm colored diamonds appeal to some, and are an exceptional value. Others will feel they have too much color. Due to its perceptible color tint, a K diamond is often half the price of a G diamond.
Diamonds in the N-R color range have an easily seen yellow or brown tint, but are much less expensive than higher grades.
These diamonds have too much color for a white diamond.
A Diamond’s Clarity grade evaluates how clean a diamond is from both inclusions and blemishes. Clarity is graded by the GIA on the following diamond clarity chart:
FL (Flawless)
No inclusions and no blemishes visible under 10x magnification
Very, Very Slightly Included (VVS1 and VVS2)
Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
Very Slightly Included (VS1 and VS2)
Inclusions are observed with effort under 10x magnification, but can be characterized as minor
Slightly Included (SI1 and SI2)
Inclusions are noticeable under 10x magnification
Included (I1, I2and I3)
Inclusions are obvious under 10x magnification which may affect transparency and brilliance
Often when people hear the term “Carat Weight,” they think it refers to the size of the diamond. In actuality, Carat refers to the weight of the diamond, not how large the stone is. Depending on the diamond Shape and how it is cut, two 1 Carat diamonds might be quite different in size.
Diamond Carat Size Comparison
The diamond images shown are a very close approximation of the actual size of a 1 carat excellent cut for each shape. Visually, the longer shapes (oval, marquise, pear, emerald) tend to appear larger to the eye than the round and square shapes.
The measurements correspond to the shape shown above, and are typical for excellent cut diamonds of 1 carat weight.
The area gives the true size of the diamond face up (as it would appear when set in a ring). For example, while the oval diamond image appears larger than the round image, the actual surface area is the same for the two shapes, meaning the difference in size is one of perception, not reality. In contrast, the oval not only appears larger than the princess cut, it actually has a larger surface area (approximately 10% larger in this example), meaning the difference is not simply an illusion created by the elongated shape.