To the expert eyes of jewelers, they look for the clarity of diamonds whenever they inspect them. It is one property after the cut that is important to them. Cut and clarity are those that put much value on diamonds that’s why they are the most precious stones when they are almost pure. Some colored diamonds have come out but most still cannot compete with colorless diamonds.
When talking about highest clarity in diamonds, this refers to vvs diamonds that means very, very small (vvs) inclusions. The inclusions are actually carbon content of the diamonds. The lesser the carbon in diamonds the higher the price will be for those precious stones. The hardness of the diamond is based on its low carbon content.
When it comes to vvs diamonds, it is only the colorless diamonds that are checked for this. Why, because colorless means purity while fancy colored diamonds have impurities that are the reason why they show color. That is why the four C’s of diamonds are cut, color, clarity and carat has become the basis for a good if not excellent diamond.
Some colored diamonds command high values mostly because of their rarity. When it comes to the standards of vvs, chances are not even the rarest of them will pass scrutiny.
It must be accepted that clarity means transparency without any impediment or obstruction. In short there is almost complete transparency for a colorless diamond. Fancy colored diamonds have their colors that would outright compromise transparency. This is the reason why vvs is only considered for colorless diamonds because they should the almost perfect quality.see here http://www.haloengagement.com/canary-diamond/