Cubic Zirconia (CZs) aren't diamonds. They have a similar appearance to the untrained eye, but it's not hard to tell them apart. Today, the team at Gold & Diamond Source is here to explain the differences between a CZ and a genuine diamond.

We'll tell you how to tell them apart quickly. But before we get any further, we want to debunk the old wives' tale that you should try to cut glass with a diamond to find out if it's real. Many diamond simulants (stones that look a lot like diamonds) are harder than glass! So don't scratch a windshield or mirror. That test isn't reliable.

The Breath Test

If you exhale on a genuine diamond, the fogginess will disappear almost instantly. A CZ will look cloudy for several seconds. This is because diamonds and cubic zirconias are composed of different materials.

  • Diamonds are made of carbon. They cool quickly.
  • Cubic zirconia is mostly zirconia and lime. They are slower to cool down and release that moisture.

However, the breath test will not separate a lab-grown carbon diamond from a genuine earth-mined stone. So keep that in mind!

Test the Weight

Diamonds are lighter than CZs. A cubic zirconia will weigh about 1.7 times more than a diamond of the same size. You'll need to pull a stone out of the setting to do this test. 

The Newspaper Test

This test also requires a loose stone. Lay the stone upside down on a page of the newspaper or a magazine. If you can see parts of the print through the stone, it's a CZ. This is because diamonds have more refraction. They bend the light and reflect it out to your eye. 

What if Your Stone is a "Fake?"

Laugh it off! Gemstone ripoffs are the oldest cons in human history. If you purchased this piece recently from a reputable source, return it to them. But if you inherited this stone and just discovered Grandma's engagement ring is a fake, the best thing to do is wear it every day in remembrance and enjoy a giggle. 

You're in good company, by the way. The Black Prince's Ruby — the "Blood-Red Souvenir of Conquest" — that adorns the Crown of Britain isn't a ruby. It's a red spinel!

In the future, be sure to buy your diamonds from a reputable dealer like us. Contact us to learn more about genuine diamonds, lab-grown diamonds and diamond simulants today.