From Wikipedia :. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals mostly a silicate, such as quartz , while retaining the original structure of the stem tissue. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material.
The petrifaction process occurs underground, when wood becomes buried under sediment or volcanic ash and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition.
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TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content. Opalized Wood: A nice piece of opalized wood from Oregon.
It is colorful, accepts a bright polish, and shows excellent wood grain. This specimen measures about 3 inches across. Some of the best specimens of petrified wood have been preserved by silicification. Two forms of silicification are common. The most abundant is wood that has been replaced and infilled by chalcedony sometimes called "agatized wood". The other form is wood that has been infilled and replaced by opal usually called " opalized wood ".
Both of these varieties can be called "silicified wood" if you are not certain of their identity. These materials can have a similar appearance that requires testing to positively identify.
However, if you have experience in geology or gemology, the tests below are very helpful in separating them. Opalized wood has a lower hardness , a lower refractive index, and a lower specific gravity than chalcedony, as shown in the table below. Lapidary-grade petrified wood: A nice piece of petrified wood suitable for lapidary work. The pore spaces in the wood have been completely silicified, and the piece is relatively free of fractures.
It also has nice color. Petrified wood like this is very hard to find. Specimen is about three inches across. Petrified wood is often used in lapidary work.
It is cut into shapes for making jewelry, sawn into blocks to make bookends, sawn into thick slabs to make table tops, and sawn into thin slabs for clock faces. It can be cut into cabochons or used to make tumbled stones and many other crafts. Small pieces of petrified wood can be placed in a rock tumbler to make tumbled stones. Only a small fraction of petrified wood is suitable for lapidary work. Poorly preserved specimens, those with lots of voids or closely-spaced fractures do not polish well or break while being worked.
Specimens with no fractures or voids and with spectacular color are highly prized for lapidary work. Collecting petrified wood can only be done on private property where permission has been obtained from the landowner, or on limited tracts of government lands where small quantities are allowed to be collected for personal use.
Before you collect, get permission and collecting rules from the owner of private property or from the government agency in charge of any government land where collecting will occur.
People have gone to jail for collecting petrified wood on lands where removing it is a criminal act. Please see our article on the legal aspects of rock, mineral and fossil collecting. Tumbled petrified wood: One of the most popular lapidary activities that uses petrified wood is rock tumbling. Small pieces of petrified wood that are free of pores and fractures are placed in a rock tumbler and tumbled with successively finer abrasives and finally with a rock polish.
The results are polished pieces of petrified wood in baroque shapes showing the color and grain of the wood. Crystals inside petrified logs: Some petrified logs contain a spectacular surprise! Cavities within them served as crystallization locations for quartz crystals such as the citrine yellow, left and amethyst purple, right shown here. Images by Petrified Forest National Park.
Louisiana palm wood: An oval cabochon cut from Louisiana Palm "Wood. Thunder Egg. Home Geology What is Petrified Wood? How Does it Form? Where are their Locations?
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