Ruby-Glass Composites vs Leaded Glass Clarity Enhancements


Ruby-glass composites and leaded glass ruby clarity enhancements are difficult for gemologists to detect. Learn how to identify these gems and procedures.

6 Minute Read

HomeLearning CenterGemologyGemstone Testing and IdentificationRuby-Glass Composites vs Leaded Glass Clarity Enhancements

Ruby-Glass Composites or Leaded Glass Treated Rubies?

During a meeting of the Laboratory Manual Harmonization Committee (LMHC) in 2007, Dr. Pornsawat Wathanakul (Scientific Advisor to the GIT member) reopened discussions on glass fracture filling in ruby. Several members had noted myriads of large gas bubbles within the newer material submitted to their laboratories. In many cases, they found the glass filled wide seams crossing facets and accounted for an ever-increasing volume of the finished product. Furthermore, members surmised from observation that the glass held the material together. In other words, the glass acted like an adhesive.

Following discussions, the LMHC agreed this treatment went beyond any “fracture filling or clarity enhancement” process. The group decided to describe this (heavily treated) material as “ruby-glass composite” on all future identification reports.

Ruby Vocabulary Revisions

The Jewelers Vigilance Committee (JVC), along with other trade organizations, submitted a brief to the Federal Trade Commission (FTC). They suggested a number of vocabulary revisions to its Guides to ensure a standard throughout the industry, such as the following:

  • “Natural” should refer to untreated rubies.
  • “Treated” should identify rubies treated with traditional methods, such as heating to modify color or healing open fissures by adding chemicals, which


Jeffery Bergman, SSEF SGC

Jeffery Bergman, SSEF SGC, founder and director of 8th Dimension Gems in Thailand, is an American gem dealer with more than 40 years of experience in gemstone and fine jewelry mining, cutting, wholesaling and retailing. His career has taken him to more than 50 countries and every continent except Antarctica. He has appeared on the BBC, CNN, NBC, ABC and GEO; and has been featured in Time, USA Today, National Geographic, Gems & Gemology and Discovery Channel magazine. He is a regular guest speaker at gem lab seminars and gemological association conferences and universities.

Related Articles

More Articles
Ruby Value, Price, and Jewelry InformationRectangular step-cut ruby</a>, 1.01 cts, 6.7 x 4.1 mm, untreated, Mozambique. © <a href=https://www.gemsociety.org/article/natural-rubies-clarity-enhanced-with-lead-glass/"https://www.thegemtrader.com/">The Gem Trader</a>. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Ruby Value, Price, and Jewelry Information

One of the most popular traditional jewelry stones, ruby is exceptionally durable. The colors of the July birthstone — always...
Read More
Corundum Value, Price, and Jewelry InformationJoel E. Arem</a>, PhD, FGA. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Corundum Value, Price, and Jewelry Information

Next to diamond, corundum is the hardest mineral known and is very compact and dense, with no cleavage. As a...
Read More
Evolution of the Pigeon’s Blood Ruby Color GradeGemstock.org" src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Evolution of the Pigeon’s Blood Ruby Color Grade

Learn how pigeon's blood ruby color grading standards have evolved and how to choose the best gemology labs for grading...
Read More
Gübelin Grades an Exceptional Vietnamese Ruby with “Pigeon’s Blood” ColorEighthDimensionGems. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Gübelin Grades an Exceptional Vietnamese Ruby with “Pigeon’s Blood” Color

How does Vietnamese ruby compare to Burmese ruby? Learn about the "Red Treasure" of Vietnam and why even experts can...
Read More

Latest Articles

More Articles
Classic Engagement Ring StonesPastel purple sapphire</a>, 1.08 cts, 5.8 mm, round cut, Sri Lanka. © <a href=https://www.gemsociety.org/article/natural-rubies-clarity-enhanced-with-lead-glass/"https://www.thegemtrader.com/">The Gem Trader</a>. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Classic Engagement Ring Stones

Emerald, ruby, sapphire, and diamond are the most popular choices for classic engagement ring stones. Learn more about these traditional...
Read More
Broken Bangle — The Blunder-Besmirched History of Jade Nomenclature: Book Review

Broken Bangle — The Blunder-Besmirched History of Jade Nomenclature: Book Review

Is fei cui a better term for "pyroxene jade" than jadeite? Jeffery Bergman reviews Broken Bangle, a new book on...
Read More
Cuprite Value, Price, and Jewelry InformationJoel E. Arem</a>, PhD, FGA. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Cuprite Value, Price, and Jewelry Information

One of the rarest of all facetable gems, cut cuprites can show magnificent deep red color. However, these beautiful stones...
Read More
Gemstone Radiation TreatmentPhoto courtesy of <a href=https://www.gemsociety.org/article/natural-rubies-clarity-enhanced-with-lead-glass/"https://www.liveauctioneers.com/">liveauctioneers.com and <a href=https://www.gemsociety.org/article/natural-rubies-clarity-enhanced-with-lead-glass/"https://www.liveauctioneers.com/auctioneer/1081/eros-auctions-inc/">Eros Auctions, Inc</a>." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Gemstone Radiation Treatment

Gemstone radiation is a common but little understood technique for altering colors. Learn how it works and what gems usually...
Read More

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!