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How to Tell a Natural Blue Diamond From a Treated Diamond

A blue diamond occurs naturally when there are traces of boron in the stone's crystalline structure. A diamond classed "fancy" with a color grade of dark, deep, intense or vivid will have a distinct and vibrant color. There are two kinds of reproduction blue diamonds on the market -- lab-grown simulations and ordinary diamonds enhanced through irradiation or high-pressure, high-temperature treatments. There is no easy test to distinguish real blue diamonds from bogus, but there are some steps that will help you avoid buying a treated stone by accident.

Instructions

- 1
  Examine the diamond's accompanying documentation. A blue diamond recently entered on the market, whether loose or mounted should have a color-grading report from a body such as the Gemological Institute of America. This report will state whether the color is natural or enhanced. If a newly retailed blue diamond has no documentation, there is cause for suspicion.
- 2
  Consider the age of jewelry containing a blue diamond. Color-treated stones first appeared in the 1960s. If a ring with a blue diamond dates back to the 19th century, it comes from a time well before treated stones were available. Establish age in various ways -- from style, from silver or gold hallmarks or from provenance, which is evidence of a line of ownership in the shape of receipts or photographs. If the jewelry predates the 1960s, it's a genuine blue diamond.
- 3
  Send a blue diamond for color testing to a body such as the Gemological Institute of America, but note that they can only test loose, unmounted diamonds. As of 2010, the service retails around $140, depending on the carat of the stone. The report will clarify if the color is genuine, and provide information on other aspects of the diamond, such as cut, caratage and clarity.

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