Have you ever heard that you can tell whether or not a diamond is real by holding it under a black light? This theory is not entirely worthless. There is some truth behind the statement and it all comes down to a diamond’s fluorescence.
Within a diamond there are traces of other minerals, some of which will glow when exposed to ultraviolet light. Special lamps can be used to determine how much a glow can be achieved with a specific diamond. A certain degree of inner glow can also be seen in direct sunlight, because sunlight is made up of various wave lengths, including ultraviolet.
It is important to understand, however, that not all diamonds fluoresce. This is a feature to be noted in about a third of all the diamonds on the market. For that reason, the black light test can be deceiving. Two out of every three real diamonds will not react to the special light source.
Also, this test is generally said to provide a blue glow in real diamonds. Again, there is some truth to that statement. Of the diamonds that fluoresce, a very large percentage will give off a blue hue. However, as many as one in five of those diamonds will glow with a different color. So, given one hundred diamonds, only 31 or 32 will actually shine with a blue hue in black light.
Some people love fluorescent diamonds, others avoid them. Generally this latter opinion is based around misunderstanding, but it really is a matter of taste. There are varying degrees of glow and, as mentioned above, many diamonds won’t react to UV light at all. It is important to understand that this is science at work. It is evidence that these stones were pulled from the earth to showcase the beauty of which Mother Nature is capable.