You can buy diamonds at diamond auctions. It is very easy to locate auctions using google.com and typing in diamond auctions. Probably eBay and www.bidz,com would be the most popular. Also look out for local auctions in your town or city. Scouring the newspapers can sometimes net you an auction at which diamonds are up for sale.
Jewelery and gem auctions are usually the best.
Some important points to remember when buying diamonds at auctions.
If you are buying from an auction where you can attend, you will likely need to register if you intend bidding. See if you can inspect the diamond s that will be auctioned. There should be a certificate to accompany the diamond or diamonds or at least some information about them. Quite often these are antique diamonds and if so will be a good buy if the price is right. You only need to establish that they are true diamonds and not some other lesser quality stone or not even a gem at all.
Firstly you should have some understanding of the value and worth of diamonds and also what your bid is going to be. This will depend on your budget and how much you want the diamonds of course.
When you are bidding, it is better not to make a bid at all until the very last minute when all the bidding appears to be done. Provided the price is still within your budget you can then jump in with a bid and not start a bidding war (which only benefits the seller and the auction house, not the buyer!).
Online auctions are different. You cannot see the diamonds but only a picture of them. It is difficult to asses the quality of a diamond in this case and you would be more interested in seeing a certificate of authenticity which you could compare the diamond with if you did bid and won the diamond
Ensure the auction house has provision for misrepresentation of product and a protection system for the buyer. You don’t want to bid and win an expensive diamond to find when it arrives that you have just got at best a poor quality diamond and at worse a worthless piece of glass.
Buying diamonds at diamond auctions can be fun but there is no substitute for doing your due diligence