Natural diamonds begin as coal that is forged deep within the earth by intense heat and pressure. This natural process can create a variety of internal characteristics called inclusions and external characteristics called blemishes. When evaluating diamond clarity, one must determine the size, number, relief, nature, and position of all the characteristics. All of these characteristics must be taken into account when determining the value. The GIA Diamond Clarity Scale features six categories some of which have sub-categories for a total of eleven specific grades:
- Flawless (FL) – No inclusions or blemishes visible under 10x magnification.
- Internally Flawless (IF) – No inclusions visible under 10x magnification.
- Very, Very Slightly Included (VVS1 and VVS2) – Inclusions so slight that 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, I2, and I3) – Inclusions are obvious under 10x magnification which may effect transparency and brilliance.
Many inclusions and blemishes are very tiny to be noticed by anyone other than a trained diamond grader. To the naked eye, a VS1 and SI2 may look exactly the same, but in fact these diamonds are quite different in overall quality. It is imperative that one has an accurate assessment of diamond clarity by a trained diamond grader.