I've been having this bizarre problem. Anytime I hold a glass with condensation -- like an iced tea, for example -- in my right hand for a bit, the skin on my ring finger starts to look sooty -- like it's covered in black dust. I wear my sapphire and 14K gold ring w/ little diamonds every day -- and it's definitely all genuine materials...so I don't know why it's turning my finger black. Anyone else ever encountered this problem?? I know that some synthetic golds turn fingers green? But this is different...and annoying!