In geology, petrifaction or petrification is the process by which organic material is converted into a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood is a common result of this process, but all organisms, from bacteria to vertebrates, can be petrified (although harder, more durable matter such as bone, beaks, and shells survive the process better than softer remains such as muscle tissue, feathers, or skin). Petrification takes place through a combination of two similar processes: permineralization and replacement. These processes create replicas of the original specimen that are similar down to the microscopic level, and require a minimum of about 10,000 years to take place.