Historically, opal has been one of the few gemstones rarely subjected to any treatments. Sugar & acid carbon deposition used to be the predominant treatment applied to only a very specific and scarce type which then resembled natural black opal.…
Historically, opal has been one of the few gemstones rarely subjected to any treatments. Sugar & acid carbon deposition used to be the predominant treatment applied to only a very specific and scarce type which then resembled natural black opal.…