Why Do We Need Gemmologists?

Is it important to be able to identify gemstones.  It is important to be able to distinguish a natural gemstone from an imitation or a synthetic.  It is important to be able to identify treatments done to gemstones. What does this bubble seen through a microscope tell us about this gemstone that tests as a ruby?

Composite Ruby

Photo by J. McKercher

We need gemmologists!
If we were not able to identify a gemstones then we would not know it’s properties and how to care for the gemstone.  Not only do we need to identify the species and variety of gemstone, we also need to be able to decide if the gemstones is natural, natural and treated, imitation or synthetic.  A synthetic gemstone is created by man and has the same crystal structure and chemical composition as its natural counterpart.  An imitation gemstone appears to be very similar to a natural stone, but does not have the same chemical composition and crystal structure.  A cubic zirconia is an imitation of a diamond.

One treatment that is done to natural rubies is a process that fills surface reaching cracks with a high lead content glass.  JCK Magazine reports that the Gemstone Industry & Laboratory conference Ruby Committee voted that glass-filled rubies must be disclosed as “Composite-Ruby, Glass-Filled, Requires Special Care”.   This is because 30%-60% of the ruby may be lead glass!   These glass-filled rubies are not as hard as ruby, not a tough as ruby, they are susceptible to many chemicals and acids that will not hurt rubies and they can suffer damage at a lower heat than rubies.  When jewellers work with composite ruby jewellery they must be  informed that this is not a natural ruby and has a lead glass component.  The jeweller could accidentally do permanent damage doing simple, basic jobs such as re-sizing, re-mounting, or re-plating with rhodium.

When purchasing a gemstone you should not pay as much for a treated, synthetic or imitation gemstone.   Some gemstone treatments are not permanent.   When selling a gemstone you do not want to misrepresent the product.  You could lose customers, lose your reputation and be at risk of law suits.

How would a gemmologist interpret the two photos of the same natural ruby?

Composite Ruby

Photo by J. McKercher

This photo of the same ruby in reflected light shows that there are surface reaching cracks that have been filled, and the bubble in the other photo both indicate that the ruby is glass-filled and should be disclosed as “Composite-Ruby, Glass-Filled, Requires Special Care”!

Your Input(Join our poll or scroll down and leave a comment)

I plan to introduce different gemstones alphabetically.  I will start with “A” (Ammolite) and see where it leads me.  Leave a comment and let me know if you have a favourite gemstone that starts with the letter “C”.  Take the poll!  Can you name a reference to a gemstone in a song, movie or book?


About Jen McKercher

Jennifer McKercher teaches gemmology at the Canadian Gemmological Association. A passion for gemstones drives Jen to learn as much as she can about the wonders of gemstones and how they enhance our lives.

Posted on June 16, 2011, in Gemmology and tagged , , , , , , , , , , , , . Bookmark the permalink. Leave a comment.

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