Is this a mineral? I found this on a beach while searching with my metal detector. It's not magnetic, but I found it in a hole in the sand I was digging. It had barnacles on it so I know it was in the ocean for a while. I had trouble searching around for it, but it looked like a picture of a website claiming it was amethyst. This didn't sound right to me I always thought amethyst was purple. Maybe some kind of quartz?
I was also thinking of polishing this and making it shiny and possibly making a jewelry pendent out of it. What kind of tools/equipment would I need to get this filed