There’s been a huge influx of lab-grown, manmade diamonds over the past decade. It’s actually gotten to the point where, to the untrained eye, a lab-grown diamond is virtually identical to an authentic one. The confusion has caused some people frustration when they attempt to sell or pawn their diamond jewelry!
If you’re getting ready to sell diamond jewelry, make sure your piece is authentic. You don’t need to be a gemologist to distinguish a real diamond from cubic zirconia (CZ) or a lab-grown specimen. Just keep an eye out for these hallmarks:
- Refraction: If you have a loose diamond (not set into a ring or necklace), flip it onto its head (the flat top surface). Then, put it on top of a section of newsprint. If you can clearly make out the letters, you’ve got a CZ diamond, not the real McCoy. The high refractive index of real diamonds means any light passing through them would be distorted.
- Heft: If you have a diamond you know is real (certified by an appraiser) and one you’re not sure of, weigh them. CZ diamonds are about 1.7 times heavier than the real thing. This only works if you have diamonds of roughly the same size that are unmounted.
- Fog it up: Have you ever cleaned your glasses by breathing on them and wiping the fog away? This same trick can apply to spotting fake diamonds. Real diamonds are heat conductors and won’t fog up. If yours does, it’s likely a clever imitation.
These are a few low-tech ways to test your diamonds at home. But, because they’re low-tech, they’re not always the most reliable. If you’re really serious about selling a diamond, swing by your local jewelry store. A jeweler will have two more reliable techniques to distinguish a real diamond from a fake one:
- Current tester: This piece of equipment runs a small electrical current through the diamond and measures the conductivity. Diamonds conduct electricity at different efficiencies than CZ or Moissanite. A jeweler will be able to give you the scoop on your diamond’s authenticity based on this reading.
- Thermal Conductivity Diamond Tester (TCDT): Using a copper probe, a jeweler will measure how much heat your diamond conducts. True diamonds are highly efficient at conducting heat and quick to cool down. A TCDT device will measure how hot your diamond gets and how fast it absorbs that heat.
It’s worth noting that none of the methods mentioned in this post will hurt your diamond—even if it’s fake! What they will do, is give you some indication if yours is authentic before you talk to a jewelry buyer or pawn broker.