Petrified Wood on the Washington Mall

I remember going to the Petrified Forest in Arizona when I took a trip out west once so I was delighted to see some pieces of petrified wood at the Smithsonian Natural History Museum on the Mall in Washington, D.C. recently.  I don't know if these pieces are from Arizona but they look very much like the ones I'd seen before.
To show how I had no idea about it, when I went to the petrified forest national park in Arizona, I really expected to see a standing forest of "frozen" wood. Feeling a bit silly, it was, of course, 'just' several acres of land that you can walk through on paths that weave among logs and trees and stumps that are lying on their sides and are fossils that were created when they got buried in sediment and minerals leached into them aeons ago.
 What is especially interesting are the tree rings and all the different colors that the minerals show in the "wood" pieces. You can touch the ones on the mall and they feel just like stone!  So interesting!