fossil wood; petrified wood
Refers to wood that has been fossilized through permineralization or replacement by minerals. Used in geology and paleontology contexts.
Fossil wood is often found in this area.
A large piece of petrified wood is on display at the museum.
珪化木 is a more technical term for silicified wood, a type of petrified wood where the original material is replaced by silica.
Compound of 木 (tree, wood) and 化石 (fossil). The reading もくかせき follows the on'yomi of the characters.