Petrified Wood
Image: <a href="https://en.wikipedia.org/wiki/User:Dschwen" class="extiw" title="en:User:Dschwen">Daniel Schwen</a> (CC BY-SA 3.0)
Mineral NamePetrified Wood
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorswhite, grey, black, red, orange, yellow, brown
Transparencytranslucent
Type LocalityPetrified Forest National Park, USA
Mineral GroupSilicates
Usesjewelry, ornamental, collector
Associated Mineralsquartz, chalcedony, jasper, agate, iron oxides
Raritycommon
Description
This image shows a cross-section of petrified wood, revealing concentric growth rings in a vibrant array of colors including white, grey, black, red, orange, and yellow, set against a sandy background.
Geological Context
Petrified wood forms when plant material is buried by sediment and protected from decay by oxygen and organisms. Groundwater rich in dissolved silica then flows through the sediment, replacing the original organic material with quartz (chalcedony), preserving the wood's cellular structure.
