The white color is petrified wood is due to the presence of Silicon Dioxide, commonly known as free Silica, occuring in the form of quartz.
Blue and purple hues in petrified wood are created by the presence of manganese dioxide.
This tan color in petrified wood is the most common color of petrified wood. In this case, the structure of the wood is preserved better and produces an appearance or actual wood. This is due to the presence of silica dioxide.
The green color in petrified wood is obtained from iron in the soil.
The red and pink color in petrified wood is produced by the presence of a form of oxidized iron called hematite. The color can be normal or more vibrant depending on the amount of hematite present in the soil.
Brown,yellow, and orange colors in petrified wood are created when goethite is present in low temperature conditions. The exact shade it imparts is a brown ochre.