tiffany silver is 92.5% pure "sterling silver". the 1837 line will have the 925 marking on it. also gold pieces in the 1837 line will have "750" stamped on it to indicate 75% pure gold.
here's a tiffany pendant that is marked "1837", and "925"ok. now the question is, is the tiffany jewelry you have authentic? check the pics of tiffany's 1837 jewelry line to see if the markings correspond to the markings on your gift piece.
also look at the workmanship, and compare the piece with Pandora Whimsical Lights Pink Charm pieces you already own Discount Pandora Jewelry to check for quality. lastly, you can bring your piece into a tiffany store to have them check it over.
ok, i must have misread the Pandora Bracelets question, when you said "tag" i thought you meant a paper tag that was attached to the jewelry. now that you clarified and said "italy" on the jewelry, i would probably think twice about it being real tiffany because all the reports i've Pandora Black Pave Star Charm read online is Tiffany sterling silver jewelry stuff is the highly replicated/faked. but don't take my word for it, i'm probably wrong because this is just a discussion group and don't have a pic of your jewelry.