You know what...You are right. I think it might be January's birthstone. Sorry about that. I tried to change the listing title, but it won't let me. Sorry for the wrong info....:-)
Topaz can also be blue, but is a little darker. Sapphire is also blue, but it is much darker and it is the birthday for September. Hope that helps a little bit, but I am quite sure that the one you are offering is costume jewelry, right? The stone might be crystal or even acrilic, but it is quite pretty.