How to tell if a Diamond is real

July 13, 2012 at 4:43 pm

Real diamonds are a rare commodity. They retain their value and an authentic, clean diamond can fetch high prices. Whether you’re buying a gift or an investment in gemstones, you want to know what you’re getting. So how do you tell if a diamond is real? Luckily there are many tests you can do yourself to check the authenticity of a stone. Here they are below.

1. The Fog Test

Real diamonds disperse heat very quickly. Using your breath, breathe hot air onto the stone. If it’s real, you won’t see fog by the time you raise it to look at it. If it’s fake, it will show fog for up to a couple of seconds.

2. Use a jeweler’s loupe to inspect the diamond.

Real diamonds usually have some cuts or flaws on them. Using a loupe to see the diamond more clearly, inspect the stone for at least some minor imperfections. Cubic zirconium and lab-created diamonds, being man-made, will have no imperfections. Also try to look for any markings on the stone: most cubiz zirconium stones will come with a “CZ” stamp. A stamp of “10K, 14K, 18K, 585, 750, 900, 950, PT, Plat” shows the setting is real gold or platinum, giving a better chance that the stone in it is real as well.

3. Request to see the diamond’s certificate

There are some big graders that provide certificates (AGSL, GIA, LGP, PGGL) and also independent appraisers affiliated with larger organizations such as the American Society of Appraisers. If you are buying a diamond you haven’t seen in person, ie buying online, make sure it comes with a certificate from a party you trust.

4. The Refraction Test

All real diamonds disperse a large amount of light so if you can clearly see or read through it, it’s a fake. But be careful — some shallower diamonds refract less light so you may be able to see through those.

5. The color of its reflections

Real diamonds will reflect in shades of gray. If you see colors or rainbow hues, it’s either a fake or low quality diamond.

6. The weight of the diamond

A cubic zirconia stone of the same size will weigh 55% more than the real diamond. Weigh them to find out whether or not it’s fake.

7. The Scratch Test

A lot of people believe only real diamonds can scratch glass but this isn’t true. Many stones are hard enough to scratch glass, and what’s more, you may damage a real diamond by doing this.

8. The UV Test

Most real diamonds, when placed under ultra-violet light, will give off a fluorescent blue color. The good news if it’s blue: it’s probably a real diamond, as 99% of fakes won’t show blue. The bad news: blue light usually indicates a lower quality diamond, worth as much as 20% less than one of comparable size. If you see a very slight green, yellow, or gray fluorescence under ultraviolet light, it may be Moissanite.

9. The X-Ray Test

Real diamonds won’t show up on an x-ray scan while glass, cubic zirconium, and crystals all have slightly radio-opaque features.

10. Get a Diamond/Moissanite Tester.

These testers are inexpensive and if you need to test a large number of diamonds it may be worth the purchase price.

11. Get it appraised by an independent appraiser

This is the most reliable, but also most time-intensive method. Look for “Appraisal (Jewelry)” in your yellow pages or come to TraxNYC’s office in midtown Manhattan, NY. You want to ask your appraiser the following questions:

  1. What is the fee for diamond appraisal? (Usually $35-75 is considered a fair price.)
  2. Will the jewelry be constantly kept in my presence? (If they say no, move on.)
  3. Do I have to make an appointment or can I walk in?
Spending some tens of dollars to find out if your valuable rock is real or fake would give most people good peace of mind. Whatever method you pick, make sure you use multiple methods for the truest sense of your stone’s authenticity.