Cubic Zirconia

• Cubic zirconia (CZ) was one of the first recognizable fake diamonds to be broadly marketed. CZs are different from diamond in that they are heavier in weight, softer in composition and easier to scratch. Under ultraviolet light a CZ will glow with a mustard yellow color, while true diamonds glow blue.
  
  

Moissanite

• Moissanite is the most difficult to distinguish from a real diamond. Moissanite is a natural crystal that consists of almost the exact composition as real diamonds. Experienced jewelers have been fooled by this crystal; often an examination from a gemologist is required to differentiate this crystal from a real diamond.
  
  

Synthetic

• Synthetic diamonds are a man-made reproduction of the original gem that meets with the same chemical composition. Synthetics are often produced inside a laboratory under controlled circumstances and marketed as such.
  
  

Artificial

• Artificial diamonds are man-made out of whatever substance is available that resembles a diamond or that can be cut and polished to resemble a diamond. Artificial diamonds are created by individuals with little or no training to be sold under questionable circumstances to unsuspecting customers.
  
  

Others

• Several substances have been offered throughout history to be passed off as real diamonds. Included among the false stones are glass, rhinestone, zircon and white sapphires.