Petrified wood is a material formed from trees that grew in past geological epochs. Such "rarities" can tell a lot. Given the age of trees, they can be used to trace the evolution of tree crops of a certain species, learn about the time of their growth and the climate of past centuries.
How the process of petrification of trees works
Under natural conditions, wood residues decay, they are processed by microorganisms. This happens in the case of free access of air. But in some cases, the dead tree is not completely destroyed. This happens when it is buried under sediments (volcanic ash, landslides, landslides, glacial moraine, etc.) that prevent the supply of oxygen. As a result, wood does not deteriorate, but petrifies over time due to the replacement of organic substances with minerals. The physical properties of wood are completely changed, and it turns into a very dense and durable material.
In most cases, the organic tissue of the tree is replaced by silica minerals (silicified wood). Basically it is opal, chalcedony or quartz. Such fossilspreserve the anatomical structure of wood. Less common is the so-called marbled wood, the main replacement minerals in which are dolomite, calcite or siderite. In addition, gypsum, barite, jet, etc. can be substitute elements. More than 60 minerals are known to take part in the formation of wood fossils.
Main properties of petrified wood
The mineral is characterized by a glassy or waxy luster, conchoidal fracture, lack of cleavage. The hardness of petrified wood, depending on the substituting minerals, ranges from 4 to 6 on the Mohs scale. On the same saw cut, you can find areas that differ significantly in structure and color.
Due to impurities present in sediments or in water, petrified material can have a wide variety of colors. So, carbon gives the tree a black color; iron oxide - red, yellow or brown; copper, chromium and cob alt - green or blue; manganese - orange or pink; manganese oxide - black or yellow.
Among the petrified trees you can find both coniferous and deciduous species. Coniferous fossils include inclusions of amber.
Texture variations
Wood that has been petrified may have a different texture. The reason for this is many factors. Let's take a closer look at the existing texture varieties of petrified wood, as well as how they were formed.
Homogeneous fossils
Includes varieties that are characterized by an almost uniform structure with different colors. The stone has an indistinct zoning, which is not explained by the difference between the color of annual rings, but only by the presence of lines that limit them. The most famous representative of this group of fossils is the so-called opal tree, which is very light in color (may be almost white) and usually retains its primary structure.
Petrified Wood Lens Texture
This texture develops in the process of filling large cells and pores of wood with chalcedony, opal, and iron hydroxides. The lenses are characterized by a linear orientation. In some cases, it is emphasized by iron hydroxides developing in the same directions.
Spotted tree
It is the most common variety of petrified wood. It is characterized by an opal-chalcedony composition with a significant admixture of iron hydroxides. At the same time, the ratio of these three components is variable, which explains the uneven spotted color and texture of the mineral. Sometimes the spotting is due to the relics of the tree, which replaces the chalcedony, keeping the outlines of the cells against the background of the opal mass. This stone has a coloration that includes various shades of brown.
Concentric Zonal Petrified Tree
The material is characterized by alternation of opal or opal-chalcedony concentric bands of different colors. At the same time, they emphasize the pattern of annual rings of a tree in a cross section. Longitudin althe cut has a linear-striped texture that is quite pronounced.
Jet-shaped petrification
This petrified wood has a carbon-opal or carbon-carbonate composition. Lines of growth rings are clearly defined and form a concentric (sometimes wavy-concentric) pattern. For decorative qualities, black petrified wood is compared with black jade or jet.
Where tree fossils are found
Most often, petrified trees are found in areas where volcanic eruptions have occurred. The most famous place for the discovery of this unique material is the so-called "Petrified Forest", located in the state of Arizona and being one of the US national parks (since 1962). The petrified trunks are up to 65 m long and 3 m in diameter.
There are also a number of other petrified wood deposits that are located in various parts of the world. The most famous and significant petrified forests are located in Argentina, Brazil, Belgium, Greece, Canada, India, New Zealand, Russia, Ukraine, Czech Republic, Georgia, Armenia, etc. Many territories are national parks or natural monuments.
Petrified Wood Applications
Petrified wood is a stone that has been used since ancient times as a raw material for making jewelry. Demand for them remains at a high level at the present time. This decorative stone is very well processed. It is perfectly cut, ground and polished, acquiring as a resulta sort of glassy sheen. Does not lose its wood texture when processed.
Varieties of petrified wood with a small contrasting pattern are used to make inserts and small jewelry, such as beads, bracelets, etc. Especially valuable is a decorative stone with clearly defined lines of growth rings. In the manufacture of jewelry, such patterns are often combined with precious metals, other stones and glass.
Also, petrified wood is used in the production of various souvenirs and interior decoration items. These can be pens, ashtrays, vases, boxes, shelves, countertops and much more. For the manufacture of such products, a material is often used that is characterized by less pronounced zoning and has a spotted-striped or large-spotted pattern. The stone is highly prized by collectors considering the trees are millions of years old.
It should be noted that petrified wood is considered a material with special healing properties. It helps a person cope with stress and fight stress, increases the vitality of the body, protects against infectious diseases and injuries. According to folk medicine, a plate made from petrified wood can relieve pain. To do this, you just need to attach it to the sore spot. In Mongolian medicine, since ancient times, for arthritis and similar diseases, petrified wood is applied to the joints (inplanks) from the Gobi desert.
