I recently soldered new posts on a pair of diamond earrings with the
stones in place and they turned quite yellow. What caused this and
how can the problem be corrected?
Here’s one possibility: If a diamond is dirty when it is subjected
to heat, the dirt can burn into the surface of the stone causing
permanent discoloration or black marks that look like inclusions. If
this is the cause, the only solution is to repolish the stones. When
soldering diamonds in place, always thoroughly clean them first and
then keep your hands off them: Diamonds are oil magnets.
Beth