I’m no chemist but my understanding is that sulfur compounds in
certain foods, tobacco smoke, sea water and some industrial compounds
can contribute to gold and silver jewelry leaving a black deposit on
the wearer’s skin. These sulfur compounds link up with the copper in
the alloy, creating blackish sulfides. Foods such as broccoli are
quite high in sulfur, as are many other vegetables such as legumes –
maybe why a diet of Mexican food yielded such a result. I have
noticed that my customers who smoke seem to have more of an issue
with this, and when I lived with a smoker (first husband), my silver
stock and finished work oxidized much more quickly. Jeweler friends
with shops near the shore have remarked to me on how quickly silver
tarnishes given the exposure to salt and sulfur. Interesting…
Susannah Ravenswing
Jewels of the Spirit
Winston-Salem NC