When I first became a gemologist in the late 1970’s I appreciated emeralds. Very little treatment over the centuries. Just a bit of oil to seal the surface-reaching characteristics and brighten the stone. Then, came Opticon a resin filler that greatly improved the overall appearance and introduced otherwise cheap material thereby crashing the emerald market. It has since recovered a bit and resins are now the norm.
I then came to appreciate sapphires – usually heated but nothing more. Then came the diffusion process, then beryllium diffusion screwing up both the blue and fancy colored sapphire markets respectively. Sapphires may still be cool but untreated reigns supreme.
Ruby? While almost always heated, the process of using a crucible with flux leeches synthetic inclusions into their natural host – sometimes making them almost indistinguishable from a synthetic ruby. Yikes!
Now the prevalent ruby has a lead-glass in-fill that makes them truly a composite of ruby and glass. Transparent material that has a $2000/carat look sells for about a hundred. Lower end stones are a couple bucks a carat. The problem is many stores are selling this stuff without knowing what it really is.
Case in point. An NGL client walks in for a ruby appraisal. The ruby is glass-filled and valued at a small fraction of what his Internet seller has offered it at. He swears off the Internet and goes to a mall jeweler to buy a legit ruby. The jeweler confirms that they do not sell glass-filled rubies and obtains a stone from a respected source. Back to NGL for confirmation and guess what? SAME MATERIAL. LEAD-GLASS FILLED RUBY. The jeweler thought they were safe. The consumer thought they were safe. The reality was otherwise as a two thousand dollar ruby sale was reveled to be a sham. This a prevalent occurrence and one that usually goes unnoticed because the public rarely checks out their purchases and jewelers do not have the equipment or expertise to verify every vendor every time.
While this material, has been around a while, it seems to now be commonplace as not only cheap Burmese but African material has been so treated. So when buying a ruby, have your source specify what they are selling and offer an unconditional money-back guarantee if it proves to be otherwise or you are not happy. Important (expensive) rubies should be certified by the GIA, AGTA, AGL or Gübelin Lab for treatment disclosures. Many other “labs” (and a lot from Asia) just do not cut it, so a certificate may only be worth the paper it is printed on. An opinion of value is then placed by an independent lab (one not ready to sell you another stone) that you trust. Remember, an appraisal is an opinion of value by that appraiser and may not be reflective of what you are paying in your transaction. The colored stone market is not only complex for individual evaluations but extremely variable because of sale conditions and markets that can fluctuate from local economies or global market conditions. You should always buy based on what you like, not an appraised value, but you should also get what you were promised.
For more on identifying gems and their treatments take our Gemstone Identification I & II class, then follow up with Gem Evaluation for pricing information and join us at the world’s best classroom, the Tucson Gem and Mineral Show.