Gemstones and treatments

[pokerface]

I am hoping to start a thread on gemstone enhancements and when these enhancements became routine. That way, if you have a piece which is known to be from a certain era, you could know that x treatment hadn't been invented yet. Can anyone tell me when topaz first started being irradiated, for example? Thank you.

 

[Richard M.]

Irradiated blue topaz made its first major commercial appearance at the Tucson gem shows 1979, I think. There are several different treatments resulting in variously saturated color grades known as Sky Blue, Swiss Blue and London Blue.

Bear in mind that prior to that time naturally occuring blue topaz was quite rare on the commercial market and its color was generally very unsaturated compared with treated stones. The blue topaz from Texas is scarce and lightly saturated. Two other mines, one in Zimbabwe (formerly Rhodesia) and another in Brazil have produced the majority of natural blue topaz. Some lightly saturated Brazilian stones are available now and then but nothing has come from Zimbabwe for years due to mine closure.

Richard M. (Rick Martin)

 

[pokerface]

Thanks, Richard!

Here are some treatments that I know of. Please feel free to chime in with additions and corrections!


Beryllium in corundum - early 2000s

lead glass filling of ruby - late 1990s

composite rubies - 2009-2011?

cedar oiling of emeralds - 1960s

plastic filling of emeralds and other treatments - 1980s (http://emeraldstone.com/treatments.html)

 

[LD]

Thanks, Richard!

Here are some treatments that I know of. Please feel free to chime in with additions and corrections!


Beryllium in corundum - early 2000s

lead glass filling of ruby - late 1990s

composite rubies - 2009-2011?

cedar oiling of emeralds - 1960s

plastic filling of emeralds and other treatments - 1980s (http://emeraldstone.com/treatments.html)

I'm not sure your dates are correct I'm afraid. Even if they were, it's impossible to know how old a gemstone is. Rough is commonly treated so even if somebody had a gemstone cut from rough today, that rough could have been mined 20 years ago. Many treatments are around for a while before they become public knowledge also so it might be easier just to have a thread with common treatments for types of gemstones.

 

[chrono]

Labs are always 2 steps behind the cookers when it comes to discovering or noting a new treatments so it is difficult to pin down when a particular treatment became routine. The other issue is also that stones can be replaced in a piece of jewellery so whilst the ring might be antique, the stone could be fairly new and this makes it harder to guess what treatment it could have undergone.

 

[Lee Little]

Beryllium in Corundum was happening accidentally for many years before they figured out how to do it on purpose.

 

[LD]

Beryllium in Corundum was happening accidentally for many years before they figured out how to do it on purpose.

Correct me if I'm wrong Lee but I thought that we could safely say it went back to the 1970s and quite possibly earlier than that?

 

[Lee Little]

Hi LD,
It could easily go back much further than the 70's as the Corundum rough simply had a few pieces of Cat's Eye Chrysoberyl mixed in. The cookers were perplexed as they were reasonably certain that they had started with no orange or yellow Sapphire rough. Once they figured out the mystery they bought all the Chrysoberyl rough they could get their hands on and did the treatment on purpose. It was the abnormal big buying of the Chrysoberyl that lead to the labs figuring out what was happening in 20??, the exact year could be looked up but serves little purpose. Best regards, Lee

 

[lambskin]

Love this thread! Can we expand it a tad by any info when synthetic color change sapphires and alexanderites were first made?