Petrified Wood: Preserving Alberta’s Natural and Human History

Designated as Alberta’s official stone in 1977, petrified wood is part of the geology, palaeontology and archaeology of the province. Petro (meaning ‘stone’ in Greek) is the root word of petrifaction, the process whereby an organism is mineralized or turned to stone. Petrified wood is a 3-D fossil that can appear like modern wood at first glance.

Figure 1. Examples of raw petrified wood cobbles and pebble from Alberta.


Petrifaction of wood involves two processes: permineralization and replacement. Both of these processes take place at the same time and involve the flow of groundwater, rich in dissolved minerals, through the wood. During permineralization, the internal and external features are surrounded and encased by minerals that have crystallized out of solution. During replacement, decomposing plant tissues are gradually substituted with minerals, which replicate the original structure in remarkable detail. Depending on the chemical composition of the groundwater, silica, calcite, pyrite and a number of other minerals can petrify wood. Quartz and other varieties of silica (SiO2) are the most common minerals: these fossils are said to be silicified. Read more