In 1953, a team of experts were tasked to create a universal grading scale to judge all clear and colour diamonds. They came up with five grades (with a sixth added later) in which diamonds were judged for any flaws or blemishes at 10x magnification. Today, these six grades are still in use by diamond professionals around the world.
1. Flawless (symbolized as F)
The ideal clarity for diamonds, flawless means that the stone has no blemishes even when looked at under 10x magnification. Only the most rare of diamonds are able to reach this level.
2. Internally Flawless (symbolized as IF)
To garner this rating, a diamond must have no flaws on the surface. The aspect that determines whether a diamond is considered flawless or internally flawless is if blemishes seen beneath the surface of the stone when looked at 10x magnification. This rating was added in the 70s as a reaction to the many diamonds that were being cut smaller than necessary to take out any possible flaws that would affect its clarity rating.
3. Very, Very Slightly Included (symbolized as VVS1 and VVS2)
This level refers to when minute blemishes can be detected on the diamond’s surface under 10x magnification but are still difficult to see. If the blemish is detectable from the bottom up it is graded VVS1. If it is detected from the top down, the diamond is graded VVS2.
4. Very Slightly Included (symbolized as VS1 and VS2)
Very Slightly Included means that minor flaws are seen at the 10x magnification scale while still invisible to the naked eye. The size of those flaws will dictate whether it gets rated a VS1 or VS2.
5. Slightly Included (symbolized as SI)
This level gets to the point of the flaws are easily seen on the surface under the 10x magnification. Though these flaws still can’t be seen with the naked eye and does not impact the diamond’s sparkle.
6. Included (symbolized as I)
There are three levels of the Included rating – I1, I2 and I3. I1 means the flaws can almost be seen by the naked eye. I2 means they can actually be seen by the naked eye. I3 means not only can the flaws be seen by the naked eye, they actually impact the spark of the diamond.