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They feel heavy and dense for their size and lap very easy. I pretty much know the min I pick one up

It looks like a really beat-up man-made stone to me. I think I'm seeing metallic looking particles in there. To be honest I would touch a razor to that stone

If it is an Escher, it's in really bad shape. It doesn't look like one to me. Any Escher I've seen isn't rounded off looking like that one and the grain looks off to me. It might be bad photography...