Agatized Pine Cone -- A pine cone that was totally replaced by Agate, keeping its natural shape intact. It is brown and slightly translucent. It also has a little bit of fluorescence in orange, under short wave UV light. From Western Sahara. From the Eocene period
Fossilized pine cone
Uintacrinus fossil (a crinoid, 65 million years old); from http://selectivefocusphotography.blogspot.com/search?q=fossils
Sea urchin skeletons
Hell's Canyon petrified wood. This rare wood, collected in the 1950s at a site now underwater at a dammed river on the Idaho / Oregon border, had dry rot and was compressed before petrification, creating its characteristic herringbone pattern.