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How to Test Gems & Diamonds

Some very experienced jewelers can tell diamonds and other precious gems by sight, but some authentication is necessary for most other people. Unfortunately, there is no one easy test to apply that will settle the matter, so for absolute certainty it's best to submit your stone to a laboratory for authentication. In the meantime, however, there are a few steps that you can take yourself.

Things You'll Need

Ultraviolet light
Electronic diamond tester

Instructions

- 1
  Apply ultraviolet light to the stone while in a darkened room. Gemstones will fluoresce, while paste jewelry -- i.e., glass pretending to be stones -- won't react at all. As of 2010, UV torches are available from most high-street home security stores and retail in the region of $15.
- 2
  Purchase an electronic diamond tester. Costing between $80 and $120 as of 2010, a diamond tester is about the size of highlighter pen and is operated by simply touching the point of the tester to the stone. The more sensitive testers will register sapphires and rubies as well as diamonds and cubic zirconias. Electronic diamond testers can be found at antiques accessories stores.
- 3
  Send your stone to a body such as the Gemological Institute of America for identification, authentication and grading. For $40 upwards -- depending on the size of the stone -- you will get a complete report that will be most useful should you wish to resell the item at a later date.

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