How can I find out the jewelry company that made my ring?

I have this silver ring that I love and my mom wants one bad. I want to give it to her as a gift. The problem is that I got it at a show from a silver vendor. I have looked for it at all the jewelry stores in my area and no one has it. One store looked in several catalogs but we couldn't find it. There is a hallmark stamp but the jeweler was not familiar it. They said I may be able to search online in a jewelry trademark directory to find the manufacturer and then they would be willing to order it for me if I can't buy direct. I don't know where to look. I looked at the US trademark website but couldn't find it. The jeweler said there is an online guide somewhere because not all hallmarks are registered nationally but instead is used to identify the company, artist etc. If I can't find it, I will have to leave the ring so they can do a search.