In the past, we have emphasized the importance of gem labs when it comes to buying gemstones. Most recently, we discussed how certain sapphires that appear to look like “Padparadscha” need to go through color stability testing in order to make sure they do not lose their color. That is, losing their color so they would no longer qualify as Padparadscha Sapphire.
We recently had a potential vendor show us a pleasant 4 carat Padparadscha with a beautiful pink orange mixture. The stone even included a GIA lab report from 2013.
We decided to submit the report to GIA for an update (in case you did not know, gem labs typically charge a reduced fee for updating an old report—simply submit the stone as an “update” and include the report number as a reference).
Usually updates occur faster than normal submissions. However, in this particular situation, the report took about 3 weeks. The results are below:
Surprisingly, the identification results changed to “Pink Sapphire.” A new comment also included the following: “The color of this stone may temporarily change when exposed to ultra-violet light.”
It appears that this was a padparadscha before labs started color stability testing. Many Sri Lankan Suppliers would often place fancy gemstones outside under sunlight during the day to improve color saturation. This questionable practice was a trade secret that was commonly performed prior to trade shows. Labs would miss this trick, and the report would misrepresent the color.
When looking at padparadschas, it is extremely important to trust your supplier.
These suppliers that use sunlight to improve color incorrectly think this is a natural treatment. An improvement method must be disclosed under AGTA ethical duties whether or not recognized by the gem lab on a report. This obligation is extremely important. Without it, an unbeknownst purchaser might purchase a color that would eventually go away making the stone unrecognizable.
We strongly suggest updated reports when dealing with someone new. This way you will be protected from paying extra for a fancy sapphire that is not really a padparadscha.
Although we were happy that we avoided the deception, we were reminded yet again about the importance of the lab’s role in our trade. We were also reminded that we must continue to be cautious when hunting for rare gems like Padparadscha.
GIA Adopts LMHC Definition of Padparadscha
This experience confirmed the new guidelines for determining what meets the new narrow definition of Padparadscha. GIA followed the LMHC’s guidelines for Padparadscha (See https://static1.squarespace.com/static/5bfbb7e6cc8fed3bb9293bf3/t/5bfe9241f950b7627afb4e27/1543410242229/LMHC+Information+Sheet_4_V9_2018.pdf)
The Information Sheet states: “The name ‘padparadscha sapphire’ shall not be applied in the following cases:
If the colour of the stone is not stable and shifting out of the padparadscha colour range (e.g. shifting to pink) by a colour stability test.”
Here was the precise situation. Before the LMHC updated its definition of Padparadscha, color stability testing was not included. Once it included it, the lab had to re-test the stone to meet the LMHC new standard of Padparadscha definition.
The Color Stability Test is just one of the new methods labs have advanced colored stone identification. We hope future clients avoid these pitfalls and find the right gemstone that is supported by a reputable gem lab.