Diamonds are one of the most desired gemstones in the world. Women and men alike enjoy diamond jewelry. The problem with so much demand is that counterfeiters and jewelers take advantage of customers and sell the fake stones or glass as real diamonds. Thankfully, telling if a diamond is real is simple and easy.
Look at the top of the diamond through the loupe or magnifying glass. Real diamonds will have sharp joins at the facets. If the joins are not sharp, it is not a real diamond.
Look at the outer edge of the diamond. The outer edge, or girdle, of the diamond should be "frosty" according the to Fred Cueller of Diamond Cutters International. He says that a "waxy" appearance is a fake.
Look for flaws. Real diamonds always have flaws like cracks that fakes cannot duplicate. It is very difficult and nearly impossible for a man-made creation to have flaws.
Look for any stamps on the inside of the setting and the stone. If there is a stamp in the stone, such as a CZ stamp, it is a man-made stone and not a diamond. Diamonds are also always set in high quality materials like gold or platinum. When looking at the setting, look for a stamp to indicate that it is gold or platinum.