Can anyone recommend how to remove old adhesive from lapis lazuli without damaging the stone?
A customer brought me a rather large lapis cabochon that had fallen out of its original setting. The stone isn’t a particularly high quality specimen, but it was a gift from the costumer’s brother, who purchased it in Afghanistan. The customer would like me to create a new setting that would allow the back of the stone to be visible.
Here’s my dilemma: the original setting was cast and the stone was set using some type of adhesive, which the original maker applied quite liberally. Can anyone recommend a way to safely remove the old adhesive from the back of the stone? I know lapis is soft and porous, so I’m reluctant to use solvents.