'Nugget' beach

You just can't beat beach combing in Washington County, Maine. We went to a new beach a couple of weekends ago. (exact location will be protected) The beach glass finds were absolutely incredible:

the 'nugget' (largest piece of sea glass of all time!)

As my mother said, "it's once in a lifetime that you find a 'nugget'!". She was the first one to find a 'nugget' on our first trip to this beach. Then, the next weekend, I found an even larger nugget at the same beach. It makes you wonder what was this before it was molded and shaped by the crashing waves? Our thoughts, an old railroad insulator: 

Any other ideas?