Technological advancements in the creation of synthetic diamonds have made many of them difficult to distinguish from the real thing. Stones like Moissanite and cubic zirconia are such good copies that they're sometimes passed off as authentic by dishonest jewelry salesmen. But while determining whether a stone is real diamond or a substitute is best left up to professionals, there are elements you can check out for yourself to see if your rock is genuine.
Perfect Diamonds Are Not Usually Real
Inclusions are flaws natural to a diamond's formation and they affect the grade and price. The fewer imperfections, the more valuable the stone. All diamonds have inclusions, although you won't be able to see them in a flawless stone, even at 10x magnification. However, they are extremely rare. Synthetic diamonds don't have any inclusions at all. If you can't see a single inclusion in your stone, you either possess a rare diamond or -- more likely -- you have a fake.
Real Diamonds Pass the Breath-Test
Diamonds are built with their own fake detector. Breathe on the stone and wait a few seconds. If the fog from your breath stays for a bit, it's likely not a real diamond. Real diamonds are heat conductors and readily dissipate any fog and steam. When the metal point of a diamond tester is pressed against a genuine diamond, the tester lights up or reacts in some other way. Order a diamond tester from an online store or take your stone to a jewelry store and have a staff member test it. No reaction on the diamond tester means you have a fake.
Look for the Signatures
If you have a loose stone, use a jeweler's loupe or magnifying glass to observe it from all angles. Look for a laser inscription of a company name or logo and an identification number, which can be used to learn everything about the stone. If the company mark or logo is affiliated with Adamas, Takara, Gemesis, Chatham, Scio Diamond Technology Corporation, Apollo or one of the other synthetic diamond manufacturers, it's a fake. If you see GIA, EGL or ASGL, your diamond is real. These are the marks of the Gemological Institute of America, the European Gemological Laboratory and the American Gem Society Laboratories.
Diamond Certificates Accompany Real Diamonds
If you're still unsure about your diamond, ask for a certificate of authenticity from the place of purchase. A diamond certificate is an official document that certifies a rock's cut, clarity, color and carat weight. Most dealers send their diamonds to a certification authority before they're made available for resale. If you can't acquire the credentials, take your stone to a jeweler who will send it to a certifying authority that can can give you a final answer.