What is the use of volcanic eruptions? At first glance, this is a natural disaster that makes it difficult and sometimes completely paralyzes life nearby. But since these phenomena are inevitable, one can find some use in them - as a result, volcanic tuffs appear. Application of this material is easy to find due to its unique properties. What kind?
Tuffs: physical properties
Being the product of a volcanic eruption, they can have a wide variety of compositions. The density also varies, which affects the possibility of using this material for certain purposes. Even near the same point, volcanic tuffs can have a different composition, depending on the difference in eruptions and the type of source rocks.
However, there is always something that all types of this material have in common: porosity. This is due to the fact that the volcanic rock is a sintered small fragments and remnants of ash and sand. As a result, it has amazing water and frost resistance, as well as lightness. As a rule, tuff is also relatively soft, although this already depends on specific samples. This property made it possible to process this type of rock without the use of complex tools - just with the help ofsaws and axes. At the same time, volcanic tuffs are not inferior in strength, for example, to granite. Well, in terms of the totality of properties, they even surpass them in some ways.
The name comes from the Latin tofus - this is how all breeds of similar origin were called in the territory of present-day Southern Italy. And to this day, this area is one of the richest in volcanic tuff.
Composition
As a rule, tuffs accompany the outpouring of neutral or acidic relatively viscous lavas. Liquid basics form rock more often during underwater eruptions. They decompose to clay quite easily.
Because different rocks can occur at the sites of the eruption, the final product can also vary in composition: contain more bas alt, liparite, trachyte, andesite and other particles.
Varieties
Depending on several factors, such as location and type of source rock, the properties of volcanic tuff can vary. This is reflected not only in its mass and density, but also in color.
In general, the color range of this material is extremely diverse: in nature, perhaps, all shades are found - from white and milky to greenish, dark brown, gray and black. However, the latter are quite rare.
Tuff is not always distinguished by low density and softness - with prolonged pressing, it can eventually transform into a material that has practically lost its porosity and is comparable in properties even with obsidian.
Deposits
Perhaps the most famous variety is tuff, which is mined near the city of Artik in Armenia. In addition to the fact that the largest deposit in the world is located there, the rock from there is well recognizable due to the characteristic purple-pink color. The local deposits are simply huge - a layer of 6-7 meters is hidden behind only a few centimeters of soil. There is another source of rock in Armenia - Ani, where yellow-orange tuff is mined.
There are also significant explored deposits near Naples and Rome, in Iceland, the African Republic of Cape Verde. Less extensive deposits are located in Kabardino-Balkaria and Kamchatka in the Russian Federation, in Georgia, Iran, New Zealand, Azerbaijan, Germany, on the territory of the famous Yellowstone Park in the USA. The main stone exporter in the world is Turkey, which also has some natural resources.
Processing and application
As already mentioned, in most cases, volcanic tuffs lend themselves perfectly to cutting. This property made it possible to use this material even before the advent of complex tools. First of all, this allowed the use of tuffs for the construction of houses. Excellent sound and heat insulation made this material indispensable for housing. Even the tuff finish improves the situation considerably, especially since it is excellent for decorative purposes. In addition, hard tufa species are also quite earthquake resistant. In the south of Italy and in Armenia, and now you can seeentire cities built from this material. Some buildings made of this material have remained unchanged for several centuries, regularly subjected to significant temperature changes. So tuff can also be called very wear-resistant.
Another use is to add powdered to multi-purpose building mixes. For example, some varieties are widely used in the construction of underwater structures. This is especially necessary if exposure to sea water is expected, which this volcanic rock perfectly counteracts, thereby increasing the chemical stability of the composition to which it is added.
Other types of rocks as additives lower the setting temperature of concrete, thereby preventing cracking. Often, volcanic tuffs were also used to obtain sculptural compositions. For example, the famous statues on Easter Island - Moai - are carved from this material. To a lesser extent, tuffs were used to make small household items.
At the same time, this type of rock also has a significant drawback for some purposes - it cannot be polished or at least given a smooth look. With any kind of processing, it remains a rough stone, which, however, can sometimes even become an advantage.
Artificial tuff
It seems that only nature could create such a perfect material. And for a long time it was believed that this was the case. Nevertheless, over time, people learned to receivesomething similar without the participation of volcanoes. Artificial, or hypertufa, is made using a mixture of sand, cement and peat. For decorative purposes, dyes are often also added. However, the man-made equivalent is much less popular than the natural equivalent, and landscape design has become one of the few areas of its application.
