It does have markings.. It looks like a COC or maybe its a 202.. hard to make out the markings inside. It does appear to have tiny.. tiny diamond chips when I look thru the magnifier. I hope that helps..
I was told it is gold plated.. if that helps any. The rubies were said to be simulated and that it had very small diamond chips. It is gorgeous. I do have trouble with jewelry myself as well as my daughter and tend to break out horribly with costume jewelry.. tho this one never broke me out. Not sure how it would do with you.. but I am sure the level of allergy has something to do with it.