Granite is a rock formed by a set of minerals.
Its composition is basically as follows:
- Quartz, a colorless mineral;
- O Feldspar (orthoclase, sanidin and microcline), responsible for the variety of colors (reddish, pinkish and grayish-cream);
- Mica (biotite and muscovite), which gives the rock shine.
The colors of granite most found in nature are gray and reddish tones, however they are found in the colors: white, black, blue, green, yellow and brown.
In addition, granites can have minerals such as: amphibole (hornblende), pyroxene (augite and hyperstena), olivine, zircon, among others.
Granite Characteristics
- Igneous rock (formed by the cooling of molten magma);
- High degree of hardness;
- Crystalline;
- Varied coloration.
History of Granite
The first people to extract and use granite were the Egyptians and, later, the Romans.
In Egypt, rock was used in the construction of pharaonic monuments and tombs as they were very concerned with aesthetics.
Already in the Middle Ages, granite began to be widely used in homes and churches. It is currently widely used in civil construction as well as for ornaments and interior decoration.
Granite Extraction in Brazil
Brazil is one of the main granite producers and is among the largest exporters in the world. Each Brazilian state has rock extraction and depending on the location, granite varies in color.
Thus, among the most valued types of granite in Brazil is the Baiano, in which the rocks are blue (Azul-Bahia); while in Minas Gerais they are lilac (Lilac-Gerais) and in the state of São Paulo, in turn, they are green (green-ubatuba).
Difference between Granite and Marble
Granite is harder and more resistant than marble, as it is basically composed of three minerals (mica, feldspar and quartz), while marble is formed by a mineral and calcite. Furthermore, granite does not have as many veins, being less porous than marble.
Regarding coloration, granite is more mixed and has black spots, while marble has a more uniform color.
One way to identify whether the rock is marble or granite is to scratch the surface: marble scratches, while granite - due to its strength - cannot be scratched.
Want to know more? Read:
- Types of Rocks
- mineral kingdom
- Earth's crust
