Gem enhancements, synthetics etc


Cobalt-Colored Composite Sapphires Now Entering the Market

NEW YORK: 28 January 2013 ― American Gemological Laboratories (AGL): Gemstone treatments are a regular issue which the gemstone trade has to contend with. In May 2012, AGL first learned of a new type of treated sapphire which was becoming available in the Bangkok market “This treatment was first described to me as a new type of lead-glass treated corundum where a blue colorant was also introduced.” indicated Christopher P. Smith, President of AGL.

In November and December of 2012, clients of the AGL contacted the lab indicating that such stones were starting to be encountered in the marketplace. Recently a couple of samples were sent to the AGL by Dr. Cigdem Lule of GemWorld International Inc. Although the stones appeared fairly transparent and had a convincing “blue sapphire” color, color concentrations were readily visible upon closer scrutiny even with the unaided eye and were obvious with magnification using a 10x loupe or microscope (figure 1 below).

“A chemical analysis readily showed a high concentration of lead in addition to the aluminum oxide of corundum, with trace elements of iron and gallium, while a visible spectrum revealed absorption bands associated with cobalt.” Smith stated (figure 2 below).

For the full press release please see the link below.

Secrets jewelry industry won’t tell
Yahoo News

Glass filled rubies sold in the US as the real deal. Above link gives an interview
Explaining glass filled rubies sold by retail Jewellers.


From: GIA website

Brought to you from the front-lines of gemology, each Dispatch features GIA researchers and educators who provide a quick overview on the latest treatments, synthetics and gem materials in the marketplace, as well as practical tips and techniques for dealing with these materials, and access to resources to help you learn more.

Lead Glass-Filled Rubies

Lead glass-filled rubies represent material that is heavily treated to improve transparency. The treatment is highly unstable, resulting in stones that can be easily damaged beyond repair.
The material is relatively easy to identify using a gemological microscope or jeweler’s 10x loupe. Tell-tale signs include: a flash-effect, large gas bubbles in a stone’s cavities, or flattened bubbles confined to wide fractures filled with glass.
Avoid any jewelry repair procedure and keep the material out of solvents, including basic household cleaning solutions.
Sometimes called composite ruby, hybrid ruby, ruby with glass, or a host of other names, GIA considers some of this material so heavily treated that it does not warrant being called ruby at all, but rather a manufactured product.

To gain a deeper understanding of this material, read “A Discussion on Ruby-Glass Composites & Their Potential Impact on the Nomenclature in use for Fracture-Filled or Clarity Enhanced Stones in General” (February 2012) and “Identification and Durability of Lead Glass-Filled Rubies” from the Spring 2006 issue of GIA’s Gems & Gemology.




You can see in the above pictures the rubies that have been treated with or infused with led crystal or commonly know as glass filled ruby. These stones, I don’t want to call them rubies as they are not any more, get easily damaged with usage and the cracks that were closed with led liquid start to show.


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