I dont have any close -in knowledge of hadrosaur skin but I believe that the geometric patterns they speak of are the segments on the hadrosaur skin.
Calcium carbonate, since it can form as a precipitrate mud, often develops very detailed fossil casts. I have big piles of fossil casts of a kind of fossil called a Pentamerides which is kind of crinoid. These things almost always are cast in CaCO3 mud and have remarkeable detail. I often use chunks of these fossils for students to learn the art of sample prep ao that they can cut em up on rock saws and mount them on mike slides so they can study and draw the internal structures .
