You just got engaged. You received the prettiest, biggest rock you have ever seen. Wait a minute. John is not made of money. You question how he could afford this. You hate the thoughts that are going through your mind but you have to know if your diamond is a fake. Many stones are used to imitate diamonds including cubic zirconia, rhinestones and moissanite. You don't want to bring it to a jeweler because that can be expensive. If you find yourself in this state, use the reflection test to ease your mind about your diamond's authenticity.
Types of Tests
Learn about the types of home tests you can conduct to evaluate your diamond's authenticity. If the gemstone you have fails many of these tests, bring it to a jeweler to professionally evaluate it. The home tests compare your gem to the properties of a real diamond. These tests include: the sparkle test, the transparency test, the water test, the fog test and the reflection test.
In addition, real diamonds are placed in a quality setting of gold or platinum, while fake diamonds are typically placed in cheaper settings. A gem that has a lot of scratches is probably a fake, as diamonds are a very hard, durable stone.
Study the reflection properties of a diamond. The reflection test makes use of the concept that light passing through an object will be dispersed into different color wavelengths. The wavelength emitted by a diamond is gray, because the light is so completely reflected by the large number of diamond facets, or faces.
Any other color reflected, such as a rainbow, suggests the diamond is of poor quality or, even worse, a fake. Genuine diamonds reflect from all sides of the diamond, while fake diamonds do not.
View your gem with different backgrounds. With a black background, a genuine diamond will not show any black spots due to its high number of facets. The light scatters inside a real diamond, preventing the black reflection. If your diamond is mounted, you should not be able to see through it to the mount itself. If it isn't mounted and you put it on top of newsprint, you should not be able to clearly read the newsprint below.
Learn the properties of fakes. The cubic zirconia is also very hard but it has an intense fire or dispersion off its facets. Light going through a cubic zirconia will scatter creating colored light. A cubic zirconia will show black spots in front of a black background. A cubic zirconia has less brilliance and sparkle than a real diamond.
Rhinestones are made from plastic. Since rhinestones commonly have a golden foil covering in the back, the stones are easy to identify. Moissanite is a rare naturally occurring gem with excellent brilliance, fire, luster and hardness. Due to its scarcity, most are now manufactured in laboratories. If you shine a penlight through a moissanite gem, it shows a double reflected rainbow, a sign it is not a diamond.