Diamonds are valued based on their combination of cut, clarity, color and carat weight. However, when looking for the absolute highest quality diamond, the 4Cs take on different levels of importance. While a stone’s carat weight is highly prized, cut and clarity are the most significant factors that determine a diamond’s quality.
Cut
A diamond’s cut refers to its proportions, symmetry and polish. How well a diamond is cut determines its ability to reflect and refract light, which gives it brilliance and fire. Diamonds that are cut to ideal proportions maximize light performance and sparkle more beautifully.
Of the 4Cs, a diamond’s cut grade has the greatest influence on its appearance. Even if a diamond has perfect clarity and color grades, a poorly cut stone will have dulled brilliance. Conversely, a well-cut diamond can make up for slightly lower grades in other areas.
For diamonds to achieve the best cut grade, they must meet exacting standards for proportions and symmetry. Measurements of the diamond’s table, crown, pavilion and culet sizes must fall within a tight range. Precise facet placement and angles are also required.
The highest cut grade a diamond can receive is “Excellent.” This means the diamond was cut with exemplary proportions and craftsmanship to achieve the ultimate in sparkle and fire. An Excellent cut grade is only awarded to diamonds in the top 3% of precision.
After Excellent, other cut grades in order of quality are:
– Very Good
– Good
– Fair
– Poor
Diamonds with cut grades of Good or higher are generally considered well-cut. Fair and Poor are noticeably substandard.
Cut has the greatest effect on a diamond’s appearance and is the most challenging factor to maximize. It takes great expertise and care to properly cut a rough diamond into a finished, polished gem. That is why the best cut diamonds command higher prices.
Clarity
A diamond’s clarity refers to the presence or absence of identifiable imperfections, called inclusions and blemishes. Diamonds are graded based on the number, sizes, colors and positions of these natural birthmarks at 10x magnification.
Diamonds with fewer or smaller flaws have greater clarity. They are more desirable because their appearance is less affected by inclusions and blemishes.
Like cut, clarity is graded on a scale. From highest to lowest clarity, the gradings are:
– Flawless (FL) – no inclusions or blemishes visible under 10x magnification
– Internally Flawless (IF) – no inclusions, only minor blemishes
– Very Very Slightly Included (VVS1 and VVS2)
– Very Slightly Included (VS1 and VS2)
– Slightly Included (SI1 and SI2)
– Included (I1, I2 and I3)
Diamonds graded Flawless, Internally Flawless or Very Very Slightly Included have exceptional clarity. VS through SI diamonds have minor inclusions, but they are difficult to see with the naked eye. The lower grades of I1 to I3 have obvious flaws and most visible to unaided sight.
When selecting the highest quality diamond, Flawless and Internally Flawless clarity grades are ideal. A VS clarity diamond can still qualify as top quality if the inclusions are small white crystals located along the girdle edges that do not impact transparency.
Color
Diamond color evaluates the absence of color in a stone. Scientifically, diamonds are crystals of pure carbon that form under immense heat and pressure deep underground. During this process, subtle trace elements may infiltrate the diamond and cause tints of yellow or brown. The less color a diamond has, the higher its color grade.
Like the other Cs, diamonds are rated on a color scale. From most colorless to most yellow/brown, the gradings are:
– D, E, F – Colorless
– G, H, I, J – Near Colorless
– K, L, M – Faint yellow
– N to Z – Light to very light yellow or brown
Colorless diamonds are the most rare and valuable. Near colorless grades also exhibit exceptional beauty. Once diamonds start showing a yellowish tint in the Faint range, their value decreases significantly.
For the highest quality, D to F colorless diamonds are ideal. Some G color diamonds with no discernible warmth can also qualify as top color grade. Anything below G will start to show increasing yellowness.
Carat
The diamond’s carat weight measures its mass. One carat equals 0.2 grams. Larger diamonds are increasingly rare and valuable. Prices rise exponentially with carat size, especially at one carat and above.
While bigger diamonds fetch higher prices per carat, they are not necessarily better. Carat is the one C that does not affect appearance. A 1 carat diamond can have the same cut, clarity and color grades as a 0.5 carat diamond. The 1 carat diamond will cost more, but the two stones will look similar face-up.
For the highest quality diamonds, you want a carat weight large enough to impress, while optimizing for cut, clarity and color. Generally, a 1 carat diamond or more with Excellent cut, IF to VS2 clarity, D to G colorless grade will qualify as top quality.
Highest Quality Comparison
Let’s compare how diamonds with different characteristics stack up for highest quality:
| Diamond | Cut | Clarity | Color | Carat | Quality Rank |
|---|---|---|---|---|---|
| A | Excellent | IF | D | 1.01 | 1 – Ideal |
| B | Very Good | IF | F | 1.04 | 3 – Good |
| C | Excellent | VS2 | G | 0.9 | 2 – Excellent |
| D | Ideal | SI1 | H | 1.5 | 4 – Fair |
Diamond A has the highest quality combination of Excellent cut, IF clarity, D colorless grade and 1 carat size. It would rank as the top diamond.
Diamond C comes in second with still outstanding grades. The slightly lower VS2 clarity and G color are near negligible.
Diamond B drops in quality ranking due to the Very Good cut, despite having higher clarity and carat weight. Since cut is most important, the less ideal proportions reduce light performance.
Diamond D would rank lowest. While the 1.5 carat size is impressive, the SI1 clarity and H color are more noticeable flaws. An Excellent cut cannot compensate enough for the lower clarity and color grades.
Conclusion
When searching for the highest quality diamond, cut and clarity are the priority factors, followed by color grade. Carat weight is a consideration, but should not override optimizing the other Cs. An Excellent cut, Flawless to Internally Flawless clarity, D to F colorless grade, and 1 carat or larger size will deliver the finest, most beautiful diamond. With those grades, you can be assured of an exceptional stone that sparkles gorgeously.
