How to buy a diamond
As mentioned in the preamble, diamonds were formed naturally deep within the Earth under tremendous pressure and extreme heat.
Because Mother Nature can not do filtering process, most diamonds can contain slight imperfections, called also inclusions. These natural imperfections have to be considered as Mother Nature genuine quality proof certificate, as diamond can not be artificially replicated with imperfections included too. Usually not visible to the naked eye, these natural birthmarks given by Mother Nature fall into two categories: inclusions (internal) and blemishes (external).
Most common ones are the inclusions. Fewer inclusions increase the value of the stone. Just as no two people are alike, no two diamonds are alike too, and they have "birthmarks". A diamond's clarity is effectively determined by viewing the gem using 10 power magnifications loupe under controlled lighting. Adorri® is following the GIA grades ranging who uses 11 clarity levels:
"Flawless, Internally Flawless";
VVS (Very-Very Small 1 and 2);
VS (Very Small 1 and 2);
SI (Slightly Included 1 and 2);
I (Included 1, 2 and 3).
The diagram showing the top view of a round-brilliant diamond visually depicts the range in clarity.
The clarity characteristics cannot be seen to the unaided eye until reaching the lower SI to I grades. Diamond clarity is measured on a scale of I3 up to FL. Inclusions shapes and sizes can vary from "ice needles", "cotton ball" and "black spots".
I3 is the worst one the scale. It's so included that it looks like there is a cotton ball trapped inside the diamond. Then higher up on the scale is SI2 (slight inclusions), and SI1 (slight inclusions). Many SI diamonds that are finely cut look a lot better than their clarity calls for. VS2 and VS1 are the next on the scale, standing for very small inclusions. IF stands for internally flawless, and then FL, which stands for flawless. In our days' jewelries stores, an internally flawless diamond is unusual, but it can be available based on firm order. A combination of D color and Internally Flawless is rare, and therefore more expensive.
The internal characteristics or inclusions shown in red are not the actual size, but are used to demonstrate how they would appear under 10X loupe magnification. Remember, the clarity features are not readily visible to the unaided eye until the SI2-I3 clarity ranges.
The "carbon spot" is a false and misleading term. Correctly, a dark-appearing inclusion is generally not un-crystallized carbon. Diamond is 99.95% pure carbon. Over 25 mineral inclusions have been found inside diamonds. Interestingly, the most common mineral inside diamonds is, in fact, minute diamond crystals within the "host" diamond.