How to Examine a Diamond, Diamond Buying Guide : Learn About Purchasing Diamonds

To accurately judge the quality of a diamond, it is advisable to use more than the naked eye. Here are common ways to examine a diamond.

Microscope/Loop : To examine inclusions, one uses either a microscope or a 10x magnifying glass called a jeweler's loop. This enables one to see inclusions in stones. Most dealers will let you use theirs.
Diamond Tester : A diamond tester uses light to verify that the stone you are examining is really a diamond. It does not guarantee quality -- just the type of stone. Most testers will still work when the stone is mounted.
Certification : If you are unsure of your diamond knowledge or the jeweler you are buying from, get a certified Diamond. The best known and reliable certification is from GIA (Gemological Institute of America) or EGL (European Gemological Laboratory). Be aware that certificates will cost you an extra $100-$200 on average.