Ok, another new one for me today. I picked up one at Myrtle Beach, SC because it looked interesting, then found a second almost identical one. Now I'm thinking it's something worth knowing!   It's dense and heavy. The top has a gray metallic sheen to it. Both of them have a middle circular area that looks rusty, and as if something had been attached there and pulled off.   The back looks completely different. Where the front is smooth and shiny, the backside is rather dull. I