Diamonds and Diamond Simulants

Diamonds and Simulated Diamonds

There are two types of diamonds: natural stones that take hundreds of millions of years to form deep below the Earth, and man-made diamonds able to grow to their full size after a few months in the lab. Other than their origins, natural and synthetic diamonds share the same properties since they are essentially the same stone. However, synthetic diamonds are 30 percent less expensive on average than natural diamonds, but both still command high prices, especially when it comes to high-quality diamonds.

Strength Test
Nothing is harder than a diamond. One way to determine whether a diamond is real is for the owner to rub a sharp edge of a diamond or diamond ring on glass. If it scratches the glass, it is a diamond. If it does not scratch the glass, it is likely cubic zirconia. However, some modern cubic zirconia stones are strong enough to make a small scratch on glass.

Heat Test
Diamonds do not hold heat at all, which is remarkable for a natural diamond whose origins lie in the upper mantle of the Earth where temperatures range from 932 to 1,652 degrees Fahrenheit. Cubic zirconia holds heat. The easiest way to conduct this test is for the owner to breathe on the stone. If the stone fogs up, it is holding in the heat from the owner's breath, which means it is cubic zirconia. If the stone does not fog up, then it is not cubic zirconia. It might be a diamond, but there is another simulated diamond stone called moissanite that also passes the heat test, so this is not a foolproof method for determining whether a stone is a diamond. However, it does prove whether a stone is cubic zirconia.

Light Test
Diamonds have a slightly higher refractive index; a measurement of how much light passes through the stone, than cubic zirconia. The refractive index is so high that owners cannot see through the diamond. The owner can perform the light test by placing a loose gemstone over a piece of paper from a book or magazine with printed words. If the owner can see the printed words through the stone, then it is not a diamond. It could be cubic zirconia or another simulated diamond gemstone. However, diamonds that have a very shallow cut, which means the stone itself is not deep, can fail this test because the interior structure is not thick enough to fully reflect light.

UV Test
A variation of the light test that gives results that are more conclusive is the UV test. It requires a UV light, also known as a black light, which produces light rays in the ultraviolet spectrum. The owner should hold the black light up to the stone. If it glows a fluorescent color, then it is a diamond. Cubic zirconia stones do not produce fluorescent light.