Diorite stone is an intrusive rock whose composition is intermediate between gabbro and granite. It is formed in volcanic arcs and in mountain structures, where it is found in large quantities in the form of batholiths in the root parts of island arcs (for example, in Scotland, Norway). Since this stone has a mottled black and white hue, it is often called "salt and pepper." Diorite is the plutonic equivalent of andesite.
What is diorite?
Diorit is the name of a group of coarse igneous rocks that consist of granite and basalt. A stone is often formed above the border of converging plates, where the oceanic falls below the continental.
Partial melting of the oceanic plate leads to the formation of basaltic magma, which rises and penetrates into the granite rocks of the continental plate. There, basaltic magma mixes with granite or melts granite rocks, rising along a continental plate. Thus, a melt is obtained that is intermediate in composition between basalt and granite. Diorite is formed if such a melt crystallizes below the surface.
Structure
Diorite stone usually consists of sodium-rich plagioclase with less hornblende and biotite. It usually contains little quartz. This makes diorite a coarse-grained rock with a contrasting mixture of black and white mineral grains.
Diorites consist mainly of feldspar, plagioclase, amphiboles and mica, sometimes with a small amount of orthoclase, quartz or pyroxene.
The chemical composition of the stone is intermediate between the composition of gabbro and felsite granite.
Historical application
Diorite is an extremely heavy stone that is so difficult to work with that ancient civilizations (such as Ancient Egypt) used beads from it to process granite. Its hardness, however, allows the diorite to be well processed and polished, and also ensures the durability of its products.
One of the relatively frequent uses of diorite is for inscriptions. Perhaps the most famous of the existing works is the Hammurabi Code of Laws. It is carved on a stele measuring 2.23 m from black diorite. The original of this work can be seen today in the Paris Louvre. The use of diorite in art was very important in early Middle Eastern civilizations, such as Ancient Egypt, Babylon, Assyria and Sumer. The stone was so valuable that the first great Mesopotamian Empire (Akkadian Empire) considered its capture as the goal of military expeditions.
Physical properties of dioritis
The physical properties of rocks are used to determine their type and learn more about them. There are various physical properties of diorite, such as hardness, grain size, wear resistance, porosity, gloss, strength, which determine it. The physical properties of diorite rock are vital for determining its structure and use.
Hardness and strength
The physical properties of diorite stone depend on its formation. The physical properties of rocks play an important role in determining its application in various fields. The stones are graded according to the Mohs scale of hardness, which grades them from 1 to 10. Stones of hardness 1-3 are soft rocks, 3-6 are stones of medium hardness, and 6-10 are hard rocks. The hardness of diorite is 6-7, while its compressive strength is 225.00 N / mm 2 . Diorite is not only hard, but also viscous, which determines its high wear resistance. Shine of diorite is the interaction of light with its surface. Diorite is a brilliant stone. Its splitting is not available. The specific gravity of diorite is 2.8-3. It is inherently opaque and its toughness is 2.1.
Diorite and Andesite
These are similar breeds. They have the same mineral composition and are found in the same geographical areas. The differences are in grain size and cooling rate. Diorite slowly crystallized inside the Earth. This slow cooling gives a large grain size. Andesite is formed when magma crystallizes rapidly on the surface of the earth. This rapid cooling provides rock with small crystals.
The bottom photo of the diorite stone shows a sample in the form in which it can look on a polished work surface, facing stone or floor tile. As a rule, it is sold as “white granite” in a carpentry workshop or building materials store.
Diorite and granodiorior
Granodiorites, medium- and coarse-grained rocks are a number of the most significant intrusive igneous rocks. It consists of quartz and differs from granite in that it contains additional feldspar plagioclase. Other mineral components include hornblende, biotite, and augite. Plagioclase (andesine) is usually a double crystal, sometimes completely enclosed in orthoclase. According to the method of formation and appearance, physical appearance, mineral composition and texture, granodiorite is in many ways similar to granite. It is darker in color due to the higher content of plagioclase.
Using
In areas where diorite is found near the surface, it is sometimes mined for use as crushed stone. It has a strength that compares favorably with that of granite. It is used as the main material in the construction of roads, buildings and parking lots; It is used as a drainage stone and for erosion control.
In the stone industry, diorite is often cut into a facing stone, tile. Ashtrays, blocks, paving stones, curbs and various stone products are made from it. Diorite stone is sold as "granite." The natural stone industry uses the name "granite" for any breed with visible, interwoven feldspar grains. This simplifies the discussion with clients who do not know how to identify igneous and metamorphic rocks.
Diorite in art
Diorite stone is difficult to use in sculpture because of its hardness, variable composition and large grain size. For these reasons, it is not a favorite stone of sculptors, although it was popular among the ancient representatives of this profession in the Middle East.
Diorite has the ability to absorb varnish, and it is sometimes cut into cabochons or used as a gem. In Australia, diorite with beautiful pink specks of feldspar was cut into cabochons and called the “pink marshmallow”.
Place of Birth
Diorite deposits are relatively rare. Deposits of this breed are scattered around the world. They are located in countries such as the United Kingdom (Aberdeenshire and Leicestershire), Germany (Saxony and Thuringia), Romania, Italy (Sondrio, Guernsey), New Zealand (Coromandel Peninsula, Stewart Island, Fiordland), Turkey, Finland, central Sweden, Egypt , Chile and Peru, as well as in US states such as Nevada, Utah and Minnesota. On Corsica, a Mediterranean island belonging to France, an orbicular (spheroidal) variety of diorite is found, which is referred to as “corsite” or “Napoleonite” in honor of its place of origin and the French leader, respectively.