So, finding the value of your diamond ring is split between calculating the worth of the Diamond and band independently.
The First Step: Diamond Grading Process
Sell diamond rings by calculating the value of the Diamond with a series of steps, easy research, and simple math.
All diamonds should have a certification/grading report from the Gemological Institute of America (GIA) or the American Gem Society (AGS).
These reports assess the quality characteristics of Diamonds Cut, Color, Clarity and Carat (also known as the “4 C’s”) in order to determine the quality grade. Looking at the average price of loose diamonds with the same quality grade can give a market price, but the selling price will be 20-30% (on the low end), and 70-80% (on the high end) of that value.
Calculating the value of the ring band is a slightly similar process when you’re trying to sell diamond rings.
First the type of precious metal must be identified.
Sterling silver will be stamped with the number 925, meaning that the metal is 92.5% pure silver (the remaining 7.5% is another metal alloy, usually copper).
Fine silver, or pure silver, has a silver content of 99.9%, but is usually too soft to make jewelry with.
Gold has a karat stamp to determine purity; 14 karat rings are about 58% pure gold, and 24 karat gold is 100% pure.
As a result, knowing the purity of the metal allows you to calculate the total grams or ounces of precious metal by weight (for example, 100 grams of 14 karat gold would yield about 58 grams pure gold).
The final steps to sell diamond rings are determining the resale value of the metal, which will be around 60-80% of the market price per gram of the precious metal, then adding it to the selling price of the diamonds.