Before I dunk the earrings in the LOS I thought I had better check
with the experts on Orchid who have come to my aid so many times.
Alma, LOS is not an especially reactive chemical or anything, beyond
it's ability to form sulphides on silver or copper alloys. But it
does have that distinctive dark color, so it can stain things. Your
solid crystaline or glass materials will be fine, just as is the
metal which lets you rinse off the LOS. You might be better avoiding
dunking in stones that are porous and could absorb the LOS, staining
them. turquoise is a prime example, at least for the typical softer
unstabilized material. Good "persian" quality, relatively hard and
dense (for turquoise) probably wouldn't be affected. Plain white
solid opal also is fine, but you'd want to avoid the sort of granular
materials that are sometimes "sugar/acid" treated, or some boulder
opals with porous rhyolite or limonite bases or inclusions. Similar
idea with Lapis. The sulphate in LOS might give it slight acidity
too. Not sure of that. But if so, pearls or acid sensative stones
like coral might also be better kept out. I don't recall ever having
any trouble with malachite though, so that's probably not an issue.
Your synthetics, or for that matter, natural stones like saphires,
tourmalines, topaz, etc, won't be affected at all. Dunk away.