Is That a Real Diamond?

Posted on Monday, April 23rd, 2018 at 4:11 pm by Sara

Have you ever seen a big diamond on someone’s hand and wondered, “Is that real?”  Well, wonder no more. You’re about to find out how not to get fooled again.

Many consider a diamond ring to be the ultimate expression of one’s never-ending love. We celebrate the most special occasions with diamonds: marriage proposals, wedding anniversaries, graduations, birthdays, Valentine's Day, and other special occasions. As a result, the jewelry industry has tried for decades to come up with other materials that look like diamonds.

The most popular simulations today are Cubic Zirconia (CZ) and Moissanite. Once you know what to look for, it’s easy to tell the difference between a diamond and one of these synthetic simulant stones!

Are there any scratches or abrasions?

A diamond is among the most valuable and beautiful creations of nature. It is also very hard, rated 10 on the Mohs hardness scale. You may have heard it’s the hardest natural substance; as a result, we often say "A Diamond is Forever." The most comparable natural substance to a diamond is Corundum, which is what comprises red rubies and blue sapphires. Though Corundum is harder than all other natural substances, the difference between it and a diamond in relative hardness is not close. A diamond is over three times the relative hardness of Corundum. Cubic Zirconia is rated 8-8.5 on the Mohs scale; Moissanite is rated 9.25 - still a far cry from a diamond (abraded Cubic Zirconia factes pictured below). 



Are there any flaws?

A diamond is formed in nature and it is possible for there to be naturally occurring internal characteristics or inclusions in the gem. They are not easy to see in all diamonds, but some have inclusions visible with the unaided eye (internal flaws pictured below).

Does it “pop” too much?

Have you ever seen a diamond stimulant on someone’s hand and noticed it almost looked too sparkly?  That is because of dispersion or “fire.” Dispersion is the separation of white light into its component, or spectral, colors. The diamond simulants have more dispersion than a diamond and look “too sparkly” when they are clean, but look less radiant than a diamond when dirty.

These are the dispersion ratings the Gemological Institute of America has assigned to these stones (fire pictured below):

· Diamond: 0.44 (moderate fire)

· Moissanite (Synthetic moissanite): 0.104 (extreme fire)

· CZ (Synthetic Cubic Zirconia): 0.060 (strong fire)


How sharp are the facet junctions?

You may ask yourself, “What in the world is a facet junction?”  A facet is a flat side on a diamond or other cut gemstone. The location where the facets meet is called a facet junction; they are straight lines or corners.

On a diamond, the facet junctions are sharp like a razor's edge. In simulants, the facet junctions are slightly rounded. This is easily seen under 10X magnification; though, in most cases, not with the unaided eye (facet junctions pictured below). 

Diamond Facet Junctions

Smooth polished girdle?

The outer edge of a cut diamond is called the girdle. One of the easiest ways that experts use to expose a simulant stone is if it has a smooth, polished girdle. Other than visible inclusions, it’s the most telling characteristic. On a round diamond, it is the outer part that gives it a circular shape. There are two kinds of girdles you will find on a diamond: faceted and polished (transparent) or smooth and waxy (translucent).

A round diamond with a faceted girdle looks round, but it actually has approximately a bazillion tiny transparent facets in a circle. If a diamond has a non-faceted girdle, the girdle will look waxy or translucent. Smooth, waxy girdles were more common in diamonds cut long ago.

A Cubic Zirconia or Moissanite stone will have a smooth girdle that is polished. You won’t find a smooth, polished girdle on a diamond.

Double what?

Last but not least, if the simulant is a Moissanite it is doubly refractive.  It shows double images of the facet junctions when you look through the fat kite-shaped facets on the sides of the top of the simulant. They are especially visible if you look at them with a magnifying glass (double refraction pictured below).

You have successful completed "Diamond ID 101." Please use this knowledge with kindness and consideration. Please don’t go around “busting” people wearing diamond simulants. It won’t make you any new friends, but you can be quietly confident with your new-found knowledge. 

Written by Douglas Flynn, GIA Graduate Gemologist