Weird, That looks a lot like the one I just dug last thursday. Your's looks just a bit bigger. I think its what they call clams breath or clams broth but I'm probably way off. Swiz
Here's another. I can only seem to identify hand made marbles, though... therefore, I believe that is machine made![8|] (ie - I have no clue.. looks clear with a white swirly glass inside)