I knew about the how if they're real, they're gritty. They definitely passed that test. Sorry for the lack of a good picture. All I have is my phone. The clasp is silver. Says silver on the back of it. Only words on the entire necklace.
I don't know a whole lot about them. My grandmother gave them to me. She's almost 80 now, and she's had them since she was about 16 or so. I do know they are real, just don't know what kind they are.