My grandfather died about a decade ago and my mom gave me the piece pictured below and a similar ring that was in his possession. She assumed that the markings on the back stood for the Aquarius sign and since I was the only other one in our family I should have it, so we went forward with that assumption for years. I took it to someone who has studied jewelry to make it into a proper necklace and he informed us that what we thought was an Aquarian symbol was actually a Native American hallmark. Well, that was a shock to me and my mom. So I started to do some light research and didn’t really find anything that looked like the making on the back, so I thought I would try here. Is it indeed a piece of Native American jewelry? Any knowledge or leads would be most appreciated. Thanks.