How much does a 10 carat flawless diamond cost?

Today, on Blue Nile, you can buy a diamond -- internally flawless, not flawless (may be able to cut to flawless) -- of this approximate weight, and pay between US$456,181 and US$479,192, depending on the cut and exact carat weight that you want.

A flawless diamond of this carat weight may become available at an auction house, where you could purchase it for the auction price. Without endorsement from Andwers, you can watch for such an auction, below.