What are the benefits of volcanic eruptions? At first glance, this is a natural disaster that complicates, and sometimes completely paralyzes, life near. But since these phenomena are inevitable, some benefit can be found in them - as a result, volcanic tuffs appear. The use of this material is easy to find due to its unique properties. Which ones?
Tuffs: physical properties
Being a product of a volcanic eruption, they can have a very different composition. The density also varies, which affects the possibility of using this material for various purposes. Even near one point, volcanic tuffs can have a different composition, depending on the difference in eruptions and the type of parent rocks.
However, something in common with all types of this material is always there: porosity. This is due to the fact that the volcanic rock is sintered small fragments and the remains of ash and sand. As a result, it has tremendous water and frost resistance, as well as lightness. As a rule, tuff is also relatively soft, although this already depends on the specific patterns. This property made it possible to process this type of rock without the use of complex tools - just with a saw and an ax. At the same time, volcanic tuffs are not inferior in strength, for example, to granite. Well, in terms of the combination of properties, they are superior in some ways.
The name goes back to Latin tofus - that is how all breeds of similar origin were called in the territory of present-day Southern Italy. And to date, this area is one of the richest in volcanic tuff.
Composition
As a rule, tuffs accompany an outpouring of neutral or acidic relatively viscous lavas. Liquid main form the rock more often during underwater eruptions. They decompose quite easily to clay.
Since various rocks can occur at the eruption sites, the final product may also vary in composition: contain more basalt, liparite, trachyte, andesite and other particles.
Varieties
Depending on several factors, such as the place of formation and the type of parent rock, the properties of volcanic tuff may be different. This is reflected not only in its mass and density, but also in color.
In general, the color scheme of this material is extremely diverse: in nature, perhaps, all shades are found - from white and milk to greenish, dark brown, gray and black. However, the latter are quite rare.
The tuff is not always characterized by low density and softness - with prolonged compression, it can eventually turn into a material that has practically lost its porosity and is comparable in properties even to obsidian.
Place of Birth
Perhaps the most famous variety is tuff, which is mined near the city of Artik in Armenia. Besides the fact that the largest field in the world is located there, the breed is well recognized from there due to the characteristic violet-pink color. The local deposits are simply huge - a layer of 6-7 meters is hidden just a few centimeters of soil. In Armenia, there is another source of the breed - Ani, which produces yellow-orange tuff.
There are also significant proven 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, Georgia, Iran, New Zealand, Azerbaijan, Germany, in the territory of the famous Yellowstone Park in the United States. The main world exporter of stone is Turkey, which also has some natural reserves.
Processing and application
As already mentioned, in most cases, volcanic tuffs are perfectly susceptible to cutting. This property made it possible to use this material even before the appearance 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 tuff decoration significantly improves the situation, especially since it is perfect for decorative purposes. In addition, hard types of tuff are also quite earthquake resistant. In the south of Italy and in Armenia, even now you can see entire cities built from this material. Some buildings made of this material have remained unchanged for several centuries, regularly undergoing significant changes in temperature. So the tuff can also be called very wear-resistant.
Another method of application is the addition of powdered in compositions for multi-purpose construction. For example, some varieties are widely used in the construction of underwater structures. This is especially necessary if the effect of sea water is supposed, 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. Volcanic tuffs were often used to obtain sculptural compositions. For example, the famous statues on Easter Island - Moai - are cut down precisely 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 drawback that is essential for some purposes - it is impossible to polish it or at least give it a smooth look. For all types of processing, it remains a rough stone, which, however, can sometimes become even an advantage.
Artificial tuff
It seems that only nature could create such perfect material. And for a long time it was believed that the way it is. Nevertheless, over time, people have learned to get something like this without the participation of volcanoes. Artificial, or hypertuff, is made using a mixture of sand, cement and peat. For decorative purposes, dyes are also often added. However, the man-made equivalent is much less popular compared to the analogue of natural origin, and landscape design has become one of the few areas of its application.