Since natural diamonds are created in a process involving extreme heat and pressure deep in the earth, this may result in internal characteristics called inclusions – or flaws, in other words. When these flaws are external, they are called blemishes.
According to the GIA, when evaluating diamond clarity, the focus is on the number, size, relief, nature and position of these inclusions and blemishes. The purer a diamond, the higher its value. A flawless diamond, according to GIA criteria, is a diamond that has no inclusions and no blemishes visible under 10x magnification – the only magnification which is taken as authoritative.
Many inclusions that normally occur in diamonds appear black in normal lighting conditions, and are dubbed as a “carbon” spot. Some other type of inclusions that may appear are inclusions in the shape of fingerprints (rare in diamonds, more frequent in rubies); presence of other small crystals or minerals in the diamond; pinpoint inclusions (minute crystals usually white in color present inside the diamond); and inclusions known as needles, because of their thin-like shape.
