Petrified wood: how a tree becomes stone

Petrified wood forms through a genuine, well understood process called permineralization, where a buried tree is infiltrated by mineral rich groundwater, most commonly silica, and the original organic material is gradually replaced by mineral, often cell by cell, while the wood's original structure, including growth rings and grain, is preserved in remarkable detail. The result is functionally a rock, generally showing quartz family hardness around 7, while still displaying the visual texture of the original wood. Color variation in petrified wood comes from trace minerals present during the replacement process, iron for reds and yellows, manganese for blacks and purples, similar to how trace elements color other quartz varieties.