Petrified wood

Wikipedia says, “Petrified wood (from the Greek root “petro” meaning “rock” or “stone”, literally “wood turned into stone”) is a type of fossil: it consists of fossil wood where all the organic materials have been replaced with minerals (most often a silicate, such as quartz), while retaining the original structure of the wood. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen. Mineral-rich water flowing through the sediment deposits minerals in the plant’s cells and as the plant’s lignin and cellulose decay away, a stone mould forms in its place.”

Fossilized wood

Fossilized wood is also known as “petrified wood” with the mineral composition of jasper, chalcedony, and, less frequently, opal; it consists of silicon dioxide only. The wood has not changed into stone but only the shape and structural elements of the wood are preserved.

Well-preserved petrification occurs only where trees after their death are quickly covered with fine-grained sedimentary rock. The outer structure of the wood is preserved in a negative form within the enclosing rock. Circulating waters loosen organic substances and replace them with mineral substances therefore it’s not a change that takes place but rather an exchange.

The crystallization process can keep the inner structural elements of the wood, the annual rings, the structure of the cells, even wormholes are preserved. On the other hand the appearance can be totally changed during the crystallization process.

The colors are mostly dull gray or brown, sometimes also red, pink, light brown, yellow and even blue to violet. The colors become stronger with cutting and polishing.

Petrified Forest

The most important occurrence is near Holbrook in Arizona (United States). There are fossils and tree trunks of up to 213 ft long and 10 ft thick belonging to the araucaria variety of plants. The tree trunks were covered by several hundred yards of sediment. Over time part of the fossilized wood was exposed by weathering from the enclosing sandstone. Nowhere is the fossilized wood as splendidly colored as in Arizona. In order to preserve this unique natural beauty spot, the “Petrified Forest” was declared a national park in 1962. That also means that no visitor is allowed to take a piece of these petrified materials as souvenirs.

There are smaller deposits on nearly all continents. Egypt supplies good quality as does Argentina, Canada and the United States (Wyoming). In Nevada (Virgin Valley), the fossilized wood shows the beautiful iridescence of opal.

It is mostly used as ornamental objects and decorative book end, table pieces and paperweights. Petrified wood is less frequently used in jewelry pieces however you can find quality Arizona petrified wood stones set in sterling silver for Men and Women jewelry.