It's not mine , my buddy owns a pawn shop , I was there today & I saw it sitting on the floor . I asked ''what is it ''Been in printing about 25 years and never seen or heard of litho limestone. How did you come about acquiring this piece?
I remember that thread , I was looking for it today , I thought it was similar to my friends piece .I didn't know what they were either until I found one recently... http://www.treasurenet.com/forums/what/559323-historically-interesting-whatsit-just-doorstop.html
https://www.ebay.com/itm/272920045352