Petrified wood is formed when minerals dissolved in ground water replaced the decaying wood of buried trees. The process of petrifaction usually takes place very slowly. Mineral solution slowly enters into the hard part of the tree, in time, wood cells are replaced by minerals. The fossil is literally petrified (turned into stone). If it happens gradually, the fine detail of the tissues is preserved. In some cases, the detail is so good that even the cell structure is preserved but the petrified fossil takes on the color of the minerals that replaced the plant. It has a measurement of 34 cm. in length, 16.8 cm. in width, 7.2 cm. in thickness.
It is rare for an organism to become a fossil. Usually, when a plant or tree dies, it is eaten or it rots away. Quick burial under layers of sediment may stop the organism from being destroyed.
The findings of paleontologist have a large and increasing importance in botanical studies. It provides the only direct evidence of life in the past because petrified wood found in any rock layer represents few of the plants actually living at that time.
This specimen which has an accession no. NMP-209 was collected in Bagong Bantay Quezon City on August 1973. Other localities of petrified wood are Cagayan, Kalinga Apayao, Pangasinan, Bulacan, Bataan, Iloilo, Bohol, La Union, Rizal, Marinduque, Manila, Agusan del Norte, Negros Occidental, Legaspi City, Cavite, Semirara Island and Zambales. Heavily silicified wood may be cut and polished but special equipment is required for this. Polished sections of petrified wood are frequently offered for sale in antique shops.