What is green slate? How is this rock formed? What minerals does it consist of? How and where is it used? In this article we will talk in detail about the origin, mineral composition and main areas of application of green shale.
Briefly about shale
Slates are a rock of metamorphic origin. They include a number of minerals (chlorite, sericite, serpentine, muscovite, quartz and others), often with relict structures - the remains of flora and fauna of past geological eras.
The properties of a particular shale largely depend on its mineral composition, as well as on the depth at which its formation took place. In general, rocks of this class are distinguished by one distinguishing feature - all of them are well stratified into separate plates (plates). In geology, this property is usually called - shale.
The rock from the earliest times is widely used in the construction and decoration of buildings. So, slate tiles were used in the construction of many buildings in Ancient Russia. Nowadays, slates are most often used as roofing material, as well as to create beautiful and stylish fences.
Green slate: photo and general description of the stone
This rock is formed in the thickness of the earth's crust under the influence of moderate temperatures and pressure. Green shales are usually present in deposits of Proterozoic and Paleozoic age, often in combination with ferruginous quartzites. Most often they are presented in the form of elongated belts.
The color of the stone is green or grayish. The texture is shale, sometimes banded. The following minerals are included in the structure of green slate:
- Albite.
- Chlorite.
- Calcite.
- Actinolite.
- Epidote.
- Leukoxen et al.
Rock origin
By metamorphism is understood the process of structural modification of a solid under the influence of sufficiently high temperatures and pressures. In geology, there is also such a thing as facies. This is a collection of certain metamorphic rocks with approximately the same conditions for their formation. There are several types of such facies. The green shale facies forms at relatively low temperatures and medium pressure.
So, the rock under consideration is formed at moderate pressure (about 6-8x10 10 Pa) and a temperature range from 330 to 460 degrees Celsius. Green shales are formed in the thickness of the earth's crust due to the transformation of volcanics (in particular, tuffs and basalts). Therefore, in their composition there is an increased content of carbon dioxide (CO 2 ) and water (H 2 O).
Basic properties and distribution
Let's list the main physical and chemical properties of green shale:
- Coloring: green or gray-green (most often).
- Hardness: low or medium.
- Structure: fibrous, fine or medium grain.
- Texture: banded, slate.
- Shine: matte or silky.
- Reaction with HCl (hydrochloric acid): weak.
Green slate is quite widespread in the earth's crust in the form of powerful stone belts. As a rule, it lies in vast areas and often borders on ferruginous quartzites, phyllites, porphyroids and some other rocks.
Rich deposits of green schists are found in many countries of the world. So, large deposits of the breed are in the USA (in the state of Vermont), Japan, New Zealand, Kazakhstan and the UK. In Russia, green shales are common in Kamchatka, the Middle and Southern Urals, Altai, and also within the North Caucasus.
Active development of rock deposits is carried out only in two states - Russia (in the Urals) and Germany (Katzenberg). The most high-quality material processing is famous for the German company “Ratshchek”. Its products are exported to many countries in Europe and the world.
Qualities of slate as building material
This breed has found wide application in the construction industry. Due to its matte luster and muted green color, the stone is also very popular in the decoration of buildings (both external and internal). It is not superfluous to list the most important qualities of building materials. Among them:
- Fairly high strength.
- Resistance to mechanical deformations.
- A wealth of shades.
- Resistance to high humidity and sudden temperature changes.
- Excellent sound insulation.
- Low water absorption.
- Aesthetically attractive appearance.
Green slate is an excellent and versatile building material. It practically does not fade in the sun and retains its color for many years. Where exactly is it used? We will tell you more about this later.
Possibilities of using the breed in construction and decoration
Green slate is an excellent building and decoration material. The composition of this rock contains a number of different minerals. Some give it strength, others give decorative qualities. Due to its layered banded structure, it harmonizes perfectly with the texture of natural wood.
Based on the cost criterion, green slate can be classified as elite building materials. Here are three main areas of application:
- Facing of building facades.
- Material for the roof.
- Landscaping.
On sale, the material is most often presented in the form of a square or triangular tile. Slate lends itself perfectly to any processing, it is well cut and does not crumble or crack. The thickness of such tiles, as a rule, does not exceed one centimeter.
Green slate is widely used for flooring in rooms, socles and building facades, interiors. He found his application in landscape design. So, stone is used when paving garden paths, as well as in decorating ponds and alpine slides. Over time, the shale may fade a little. To prevent this from happening, it is recommended that it be periodically treated with special formulations.
Green slate is perfectly combined with other building materials (granite, marble, etc.), as well as with natural wood. Therefore, it can be safely used to create a wide variety of landscape compositions. However, the most popular area of application for oil shale is roofing. For this purpose, it is necessary to choose a tile of the highest quality, without any cracks or chips. Facing the green slate with chimneys, attic windows and various turrets looks very successful and stylish. A variety of colors and shades of this material allows you to create the most unusual patterns on the roof of the building.