How much is a perfect 10 carat diamond worth?

The largest Flawless, D Colour diamond for sale today on Blue Nile weighs 7.65 carats and sells for US$1,167,550 or US$152,621 per carat. (You can calculate your 10-carat estimate from this per carat value.)

You may be able to find a different 'perfect' and differently coloured diamond at an auction house that weighs exactly 10 carats. The diamond could be a Deep Fancy yellow, blue, pink, or other colour. There, the price will be established by the bidders in the room at the time of sale.

A deep fancy coloured diamond that is flawless and large will probably cost you more per carat than the D colour diamond, above.