Every so often jewellers need to do repairs on items that have gems in them. If the repair requires soldering, then one needs to evaluate whether the gems will be able to withstand the heat required to solder close to them, or whether it will be safer to remove the gems first.
Gems that are set can often be unset. If they can’t, well, then the item probably cannot be repaired without burning the stone or altering its colour…
As a rule, any organic gems (these include pearl, mother-of-pearl, shell, blister and mabé pearls, wood, bone and amber) cannot withstand the heat required for soldering and needs to be removed before a repair is attempted. Incidentally, many organic gems are also too soft to set and are glued into their settings instead, which potentially makes them a bit easier to remove.
The best way to take out gems that are glued is to heat them, though not to the point where they can burn. Heat softens the glue enough that the gem can be pushed out or the glue can be lifted off the back of the setting to loosen the gem.
A gentle way to heat jewellery with organic gems in is to hold it under a tap of running hot water or to steam it with a steam cleaner. If this method does not work the first time around, repeat it until the glue eventually softens or becomes brittle.
Another method is to use a soft flame from your soldering torch and play it around the setting, taking care not to heat the gem directly. This normally provides the quickest results, but there is a bit more risk of damaging the gem. If you are going to attempt this method, clamp the jewellery item with tweezers and then use an old hand towel through which to handle the gem so that you don’t burn your fingers!
Once the gem is out, make sure to remove all the excess glue from the setting before soldering. Glue that has burnt goes pitch black and the residue can be remarkably hard to remove. If the glue does burn, your best option is to use a bur in your hand drill to scratch the black bits off.
Because heat softens glue, it is not recommended to leave jewellery with glued gems in the sun or in a hot car. Neither should one bath or shower while wearing jewellery with glue in them.