Have the ring appraised. The value of a diamond is calculated through a number of factors: color, cut, clarity and carat weight. Only a professional jeweler can determine the correct grading for the diamonds in your ring and provide an approximate value for the ring as a whole..
Sell the diamond rings online. There are a number of sites where you can advertise the sale of the diamond rings, such as Ebay and Craigslist. Include all of the pertinent information, such as the specifics about the diamond (cut, color, clarity and carat weight), the type of metal used for the setting (such as gold or platinum) and the size of the ring. Post the information, along with your asking price and contact information. After payment by the buyer, send out the ring with shipping insurance or meet in person to conduct the actual sale.
Bring the rings to a jeweler. Many jewelry shops purchase unwanted jewelry, but at a lower-than-retail price. The offer--which could be cash or store credit--is usually dependent on the current price of gold, if the setting contains the metal. Selling a diamond ring in this manner is a good option if you are not concerned about recouping the full price of the jewelry and are in a hurry to sell it.
Visit a pawnshop. Again, you will likely receive a lowball offer. Show the shop owner all of the information relating to the ring, such as the appraisal and diamond grading report. This type of buyer generally pays in cash and it's a quick transaction.