The situation sometimes occurs where selling a sapphire is needed.
It is important to understand therefore that you will not always get what you expect when selling a sapphire.
The best place to sell a sapphire is of course privately or through an auction. If you sell to a dealer you will not get a good price as the dealer will also want to onsell the stone and make his money and often they do not sell retail but to another dealer who may then sell retail.
If you have an antique sapphire then you could get an even better price for it due to its antiqueness and the fact that the quality of the sapphire could also be very good.
If you think you have a top quality sapphire, such as a deep blue, then it is a good idea to get the sapphire valued by an independent gemological laboratory and the quality details issued on a certificate. This certificate can then be presented with the sapphire and command the top price for that particular quality sapphire.
Selling by auction is one of the best ways to see. Do ensure that you set a reserve price of course. One of the aspects of selling by auction that people overlook is the fact that your buyer or the person who wants the sapphire most may not even be looking at the auction when your sapphire is being offered.
You might even need to list it several times, especially if it is an expensive one. The more expensive the sapphire the longer it may take to sell as the less people would be in the market for it.
eBay and Bidz.com are the two most popular auction houses that come to mind but if your sapphire is a large 'rock' then you might even consider Sotheby's or Christies auction houses. One would then auction with other gems at a 'gem' auction and would more likely find a buyer.
In this case a proper evaluation is very important. No buyer is going to buy a large sapphire with it.
Keeping the above in mind will go a long way to ensuring that you get a satisfactory price for your sapphire.