Diamonds...........

[10ClarionSt]

When a jeweller looks through the small magnifying glass at diamonds, what are they looking for? I know they can tell if a diamond is fake or not but what do they look for? What is, or isn't, in the diamond to confirm it's authenticity? Thanks.

[Fitzer]

They're looking at the clarity, the colour and the cut, all of which affect the quality/price. The ability to detect a fake is fairly simple as no other substance reacts to light quite like a diamond but this is a matter of practice and comparison, either actual or memorised. There are now synthetic diamonds which are 'real' ie. pure carbon, but these are often distinguished by being too perfect. The colour of white diamonds varies in scale from D through Z (although I think only up to M are considered jewel grades) and from flawless F to I3 which are flaws (inclusions) that can be seen with 10X magnification. How well the stone is cut is also examined, is it symetrical, is it a good cut for the stone, certain cuts enhance certain shapes and colours.

There is quite a good guide here http://www.thediamondbuyingguide.com/diamondgrading.html