Metal(s): Silver plating on the hoop(s), sterling silver on the hooks. Please note that the wrapping wire may not be silver, although it's not on the part that touches the ear
In many ancient cultures, opals were considered VERY lucky! I mean, how could they not? They look like pieces of the rainbow (and were regarded as just that). Rainbows were VERY lucky in olden times, and are still considered so!h
However, opals began to get a bad reputation and were associated with curses and bad luck. This ultimately came from their popularity... During the Black Death. Mind you, they were wildly popular for centuries BEFORE the Plague, but people seemed to forget that. Anyway, peeps started conflating wearing opals with catching the Bubonic Plague. Since practically everyone was wearing the popular stone AND so many people succumbed to the Black Death.... their association with bad luck was born.
Then, tie into the fact that a seemingly magical rainbow stone became associated with witchcraft and black magick (something Christians in the Middle Ages did not like, surprisingly), and you have a recipe for supposed cursed stones.
But let's be very clear: This isn't the Middle Ages, we have antibiotics and vaccines, pagans aren't scary, and opals are beautiful. But, if you're still leery, it may make you feel better that an October baby crafted these (since apparently those are the only people unaffected by an opal's bad luck *shrug*).