How can you tell whether a diamond is real?

Diamonds

Assuming the diamond is yours, the traditional way is to try to cut glass with it, although this is not recommended, as it may damage the setting. The easiest way is simply to walk into any jewelry store that buys jewelry (many do) and tell them you're thinking of selling it. They will pull out a jeweler's loup, examine the stone and size it in about two minutes. If the stone is a fake, they'll tell you instantly. Just be aware that if the stone is genuine, the price they quote will be about half what you originally paid for the new ring.

If you're buying a stone from a reputable source, it should come with certification papers and you can have it appraised by another jeweler, as well. Most stores allow you to return the diamond within 3-7 days for a full refund.

If you're speculating about someone else's ring, it's difficult to impossible to be sure. Cubic Zirconias and other fakes look so convincing that people couldn't tell if Paris Hilton's megawatt stone was real or not. I'd try to judge by the person's general socioeconomic status. Someone who buys their clothes at Walmart is unlikely to be sporting a genuine five-caret stone. Celebrities and the wealthy DO wear fakes from time to time, especially to prevent theft if traveling. (If the diamond is not yours, a second question might be, why do you care if it's real?)

Answer

Pressing it hard and firm on glass should scratch or yet, cut right through.

• Most diamonds have natural inclusions within them - CZ are flawless because they are man made. Use a magnifying glass to check your stone or borrow a jeweller's eye loop.

Answer

The best way to tell if it is real is to have it tested with a thermal diamond tester. Virtually all jewelers have this, it basically checks how fast heat is conducted through the stone - diamond of course is extremely good at conducting heat.

Tests like 'scratching glass' are very old tests derived from when many imitation diamonds were in fact made from glass...most diamond simulants including CZ, moisanite, etc. can readily cut glass so this test no longer provides any useful information.

Separation of synthetic diamond (man-made diamond) from real diamond is almost impossible with hand-held tools like thermal probe etc. It is recommend to get your stone tested by a reputable gemological lab.

First answer by Joni. Last edit by Webuff. Contributor trust: 11 [recommend contributor]. Question popularity: 66 [recommend question]