This is a Fossil Dinosaur Coprolite or Poop from the Jurassic Age period. It was found in Utah. This piece measures approx. 33 x 23 mm: thickness is 6 mm: weight is 9 grams.  
 
Coprolites are in essence fossilized fecal matter or POOP. There are a few factors that determine shape, constancy, perhaps color of dung. Turns out you can polish a turd, although I must admit it is not easy