Could that “girl’s best friend” actually be a phony? Say it ain’t so. Long before Marilyn Monroe sang of the affinity between a woman and her bling in the 1953 classic Gentlemen Prefer Blonds, the diamond had become an icon of cultural resonance — not something that could (or should) be faked. The ancient Greeks considered diamonds tears of the gods. The pharaohs thought they signified power. Louis XIV would have agreed: For one especially important meeting, he made an impressive show of authority in a suit embroidered with diamonds.
Only the real thing could have that effect.
So, how can you avoid being taken in by a fake diamond? We reached out to experts for DIY methods of distinguishing genuine gems from impersonators like moissanite or lab-made cubic zirconia.
While eager to share tips, they cautioned that only a professional appraisal is guaranteed to be accurate. “Have your diamond GIA certified,” says Alexandra Nova, director of sales and marketing at Jack Weir & Sons. “If you’re buying from a credible dealer, they should be providing you with a GIA certificate or an alternative.”
Another caution: Distinguishing between natural and lab-grown diamonds is something you can’t do on your own. “It requires a special machine,” says Michael Malakov, of Roman Malakov Diamonds, who graduated from the GIA Diamonds program. He notes that it’s worth the trouble, because natural diamonds cost about 90 percent more than those from a lab.
Here are some tests you can perform and details you can look for on your own.
The Scratch Test
This test requires a low-power magnifier, which you might already have at home. “Cubic zirconias have a lot of scratches,” notes Malakov, “but you can’t really scratch a diamond.” So look for scratches. Or take a chance and rub the gemstone against sandpaper — a real diamond will maintain its brilliance; the imitations won’t.
The Water Test
This requires only a full glass of water and a loose stone. Drop the stone in the glass. A true diamond will fall quickly to the bottom, while most fakes will float and sink slowly. “A diamond has a high density,” explains Nova, “so it should get to the bottom of the glass much faster than cubic zirconia.”
The Fog Test
Breathe on the stone. The resulting fog will dissipate immediately if it’s a diamond and linger if it’s a cubic zirconia or moissanite. Natural diamonds, which come from the hot core of the earth, are remarkably efficient when it comes to conducting heat.
Put a loose stone on top of the print in a newspaper, magazine or book. If you can read the text underneath, the stone is likely a moissanite or cubic zirconia. “A real diamond has enough facets to refract the light,” says Nova, “so no text should be coming through.” Similarly, you shouldn’t be able to see the setting beneath a mounted diamond.
If you set a true diamond next to a moissanite or cubic zirconia of the same color and clarity, the diamond will reflect more light, giving it greater sparkle.
Consider the Setting
“People come to me all the time with things that they have found,” says Malakov. To determine whether the stone is genuine, the first thing he looks at is the mount. “When something is set in sterling silver,” he explains, “it’s a red flag that it’s not real.”
In addition to being less expensive (and why set a pricey stone in a less pricey setting?), sterling silver is soft, so the stone is more likely to come loose.
One caution: Don’t confuse sterling silver, marked 925, with rare and very expensive platinum, which may be marked Platinum, PLAT or PT.
Check the Color
It takes a certified professional to determine the color grade of a diamond, which goes from D (colorless) to Z (light yellow or brown). Hues J to Z, however, can be distinguished by the naked eye. So, a colorless gem should raise suspicions. There’s a small chance it may be an extremely rare grade D diamond, but as Malakov points out, “cubic zirconias are all white.” Colorless and common. Consider the odds.
Examine the Facets
“If you put a diamond to the light, the angles of the facets of a real diamond are very sharp and meet perfectly,” says Malakov, noting that by contrast, “in a cubic zirconia, the angles aren’t very straight, and they don’t meet perfectly — you might have some facet overlapping or some extra facets.”
Most high-quality diamonds “will have facets on the girdle,” adds Nova, referring to the thin band that touches the setting and divides the bottom of the gem from its crown. “Instead of being perfectly smooth, it should look like someone made little marks with a blade around the girdle. It’s a very specific thing that you can probably see with a loupe.”
Look for Flaws
It’s estimated that fewer that 0.5 percent of natural diamonds have no inclusions, minuscule imperfections that occur when a stone is formed 100 miles below the earth’s surface. “If it doesn’t have any inclusions, it’s very likely that it’s not a natural stone,” says Nova. Indeed, she continues, a five-carat diamond without any inclusions is either lab-created “or it costs more than a hundred thousand dollars.”