Petrification is the geological process in which organic material (including wood, bone) is turned to stone slowly over time. Are all fossils petrified? No. There are also compression fossils, impressions (also known as molds), casts, and trace fossils. Is everything fossilized? No, an incredibly small percentage of life has been fossilized. Approximately less than one tenth of one percent of all species that have ever lived became fossils. #MNH #Dinosaur #Fossil Video description: still photos