Concur with 10X magnification for a loupe, as it is the industrial standard for determining "clarity" of a diamond.
Check out this link to White Flash's definition of "Eye Clean", very good read:
White Flash's Definition of "Eye Clean"
Cut is the most important of all 4Cs, as it gives the diamond the sparkle. A good cut diamond looks more sparky than a bad cut one, and can make a warmer (Is and Js) coloured diamond look whiter. An well-cut J can be mounted on platinum without showing up as warm.
Colour is very personal, some can deter colours much better than others. Once mounted in jewellery, it is very difficult to distinguish colours from H and up, except for trained eyes, or putting the stones side by side in good light.
Eyeclean can be as low as SI2, depending on the location of the inclusion, and the shape of the diamond. Brilliant cuts such as Round and Princess can "hide" inclusions better than step cuts such as Emerald and Asscher.
A well cut H/VS grade diamond is much better value for money than an average cut D/IF for majority of cuts. If cut and carat size are equal, then a H/VS will definitely be better value than a D/IF.
For diamond jewellery, if the diamonds are very small, i.e. 1mm or smaller, then the colour and sparkle factor are more important than clarity.
Pricescope, the diamond forum that does not allow much talk on pearls, is a great resource about all things diamonds and coloured stones, and one can browse freely without being a member, just like this forum
DK
