Treatments and Synthetics: A Visual Review by John Koivula

johnk1 John Koivula an Analytical Microscopist at the Gemological Institute of America shared a visual review of slides identifying common features for synthetic and treated rubies, sapphires, emeralds, diamonds, chrysoberyl, opal, spinel, quartz, jade, and corundum.

The majority of characteristics seen in treated and synthetic gemstones can be seen with the standard gemological microscope used by most graduate gemologists and appraisers.

What is needed to identify treated and synthetic gemstones?

  1. A well trained and educated mind.
  2. Keeping an open mind to consider all possibilities.
  3. It also helps if you have a network of people you can consult with, which is what the GIA Alumni Chapters provide locally, and GIA GGs provide globally.
  4. Know every manufactured imitation.
  5. Know every type of synthetic gem material.
  6. Know every method of treatment

True synthetics have been produced and sold into the gem trade over a 100 years, ever since the introduction and fraudulent sale of so-called Geneva rubies in the 1880s, and with the countless numbers of treated stones, it never hurts to reexamine the main identifying characteristics of some of the most important of these materials.


GIA web pages provide resources via online articles and past Gems & Gemology Magazine articles covering many treatments and synthetics.

An introduction to synthetic gemstones;

DCGIA thanks John Koivula for sharing his industry knowledge with us and we look forward to his future offerings in print and on-line.


Summary by Charles Marts

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