Why is F/SI1 my favourite grade

Firstly, for the uninitiated what does F/SI1 mean. F is colour and SI1 clarity. It is just a trade abbreviation for colour/clarity. I love F colour (or higher) because this is into the colourless range of diamonds - D, E and F are colourless and G, H and I are near clourless. SI1 with GIA's strict standard (not so for HRD) never has a visible inclusion in the diamond and therefore the question can be asked "why pay more".

Now I must balance the above with some caveats. I have sold several diamonds, for example, a 2 carat G colour Internally Flawless ($45,000 in NYC). This diamond was remarkable looking. Similarly I often sell H colour, VS1 diamonds and these are pretty darn special too.

So for a while I was on the fence between F/SI1 and H/VS1 but I think I will continue to be an F/SI1 guy especially because I hand pick the SI1 diamond such that its inclusions have zero effect on the diamonds appearance. Hope I did not baffle you with science too much as I vent my opinions here!

Call me ... buy a diamond!

Diamond Certification

Certification is my major bug bear of the month. I am doing a lot of appraisals and the results are surprising to say the least.

What about an HRD certified (from Antwerp) "SI1" clarity diamond with 3 large visible black marks in the diamond. You would never have even one visible mark in a GIA SI1 clarity diamond. On closer inspection, the diamond also had a large white feather inclusion which in itself would have made this diamond an I1 clarity grade by GIA's strict standards. Worse still this inclusion was not marked on the diamond plot which is a diagram of the diamond and it's inclusions actually drawn on the certificate by the gemologist.

As another example, what about a 1 carat, D colour, VS1 clarity diamond certified by IGI from Dubai. This diamond cost the customer about $5000 and I can tell you that it was nowhere close to a GIA D/VS1. In fact it was closer to a G colour, Si1 clarity diamond. You could never by a 1 carat D/VS1 for $5k. The old saying is true - if it is too good to be true in probably aint true.

You should insist on GIA wherever you buy. Accept no other certificate.