Before learning about the different types of minerals, we will first understand what are minerals. They are formed by geological processes and are usually found inorganic and solid in nature. There are also few organic materials, such as silver, gold, diamond etc they are found in the earth’s crust. Today, there are more than thousands of minerals recognized but only a few of them are common. A mineral is formed through natural processes and it possesses definite chemical composition. We can identify minerals by their characteristic of physical properties such as crystalline structure, hardness, streak, and cleavage. Different gemstones like diamonds, emeralds and sapphires that are produced in industries are identical. Hence they are called man made minerals.
In this article we will explain the classification of minerals, how are minerals classified and the importance of how we classify minerals.
How Many Types of Minerals?
Minerals are mostly classified based on their crystal form Classification of minerals is of two types namely metallic and non-metallic.
[Image will be Uploaded Soon]
1. Metallic Minerals
Metallic minerals have lustre property in their appearance and they consist of metals in their chemical composition. These minerals serve as a potential source of metal and we can extract it through mining. Manganese, iron ore and bauxite are examples of metallic minerals. Metallic minerals can further be divided into two types : ferrous and non-ferrous metallic minerals.
Ferrous minerals mostly contain iron whereas non-ferrous minerals do not contain iron elements.
2. Non-metallic Minerals
Non-metallic minerals are minerals that either show a non-metallic lustre or shine in their appearance. The concentration of available metals is not present in their chemical composition. Limestone, gypsum, and mica are the most common examples of non-metallic minerals.
Bauxite ore mostly exists in deeply weathered rocks. Volcanic rocks contain bauxite deposits in some regions.
Iron metal extracted from iron ore. It never exists in the pure form we have to extract it from iron ore by eliminating the impurities.
Gold is the oldest and most precious element that is known to us.
Manganese ore is a silvery brittle or in the form of grey-white metallic ore that occurs in many forms and we can find it worldwide.
Chemical Composition of Minerals
Nearly about 98.5% of Earth’s crust is made up of only eight elements. These eight elements are oxygen, silicon, aluminium, iron, calcium, sodium, potassium, and magnesium. These are the elements that are made up of most minerals.
All minerals have a specific chemical composition. The silver mineral is made up of only silver atoms and diamond is made only made up of carbon atoms, but most minerals are made up of chemical compounds. Each mineral has its own chemical formula. Quartz is made of two oxygen atoms bonded to a silicon atom, and its formula is SiO2. If a mineral contains any other elements in its crystal structure, then it is not quartz. A hard mineral that has covalently bonded carbon is known as diamond, but a softer mineral that also contains calcium and oxygen along with carbon is known as calcite.
[Image will be Uploaded Soon]
The structure of calcite shows the relationship with calcium (Ca), carbon (C), and oxygen (O) minerals.
Some minerals have a range of chemical composition. Olivine is always made up of silicon and oxygen as well as iron or magnesium or it contains both.
Minerals are classified according to their chemical properties. Except for the native class element, the chemical basis for classifying minerals is the anion. It is the negatively charged ion that usually shows up charge at the end of the chemical formula of the mineral. For example, the sulfides are based on the sulfur ion, and it is represented as S2-. Pyrite, for example,FeS2 , is a sulfide mineral. In some cases, the anion is of a mineral class is in the form of polyatomic, such as (CO3)2-, it is the carbonate ion. The major classes of minerals are given below:
Silicate is a polyatomic anion, (SiO4)4-, which is the tetrahedral shape. Most minerals that are found in the earth’s crust are silicate minerals. All silicate minerals are built of silicon-oxygen tetrahedra (SiO4)4- in different bonding arrangements that form different crystal lattices.
These are based on the sulfide ion, S2-. Various examples include pyrite FeS2, galena PbS, and sphalerite ZnS in its pure zinc form. Some sulfides are mined as sources of metals like zinc, lead, copper, and tin.
These are based on the carbonate ion, (CO3)2-. Calcite, CaCO3, and dolomite are carbonate minerals. Carbonate minerals dissolve relatively easily in water, especially in acid water, and natural rainwater is slightly acid.
These are based on the oxygen anion, O2-. Different types of iron oxides include hematite Fe2O3 , magnetite Fe3O4, and pyrolusite MgO.
Halides have a halogen element present in the anion form, whether it be fluoride F-, chloride Cl-, bromide Br-, iodide I-, or astatide At-. Halite, NaCl, is a halide mineral.
Sulfates have the polyatomic sulfate ion, (SO4)2-, present in the anion form. Anhydrite, CaSO4, is a sulfate.
Phosphates have the polyatomic phosphate ion, (PO4)3-, as the anion. Fluorapatite,Ca5(PO4)3F, which makes our teeth hard, is a phosphate mineral.
These elements are made of only a single element. Gold (Au), native copper (Cu), diamond and graphite are made of carbon, are they all are native element minerals. Therefore, the elements that are purified and crystallized in a laboratory do not qualify as minerals, until and unless they have also been found in nature.
Examples of Minerals
Minerals are solid substances found in nature. They are not alive. The atoms which made up a mineral are fitted together to form a crystal. The chemical composition of these kinds of atoms is in the form of crystals. It is the same for every crystal of that kind although impurities or matter that is not part of the crystal may be included. Gold, diamond, rock salt and graphite is used to make the “lead” of pencils.
A piece of green coloured plastic may look identical to the emerald structure. The Mols hardness test a streak test, colour, luster, cleavage and fracture are all ways of identifying minerals.
Uses of Minerals
Mineral like copper is used in electrical equipment as it is a good conductor of electricity. Clay is used to making cement etc which helps in constructing roads. Fibreglass cleaning agents are made of borax. Given below are the uses of minerals in our everyday life:
Uses of minerals in the body
Uses of metallic minerals
Economic uses of minerals
Various other applications of minerals are used in constructing the building, developing weapons for defence, machinery, making of jewellery, synthesizing fertilizers etc.
Physical Properties of Minerals
Following are the physical properties of minerals:
Colour: It refers to the colour of the mineral.
Streak: It refers to the colour of the mineral’s powder.
Luster: It refers to the way light reflects off the mineral’s surface.
Specific Gravity: It refers to how heavy the mineral is relative to the same volume of water.
Cleavage: It refers to the mineral’s tendency to break along flat surfaces.
Fracture: It refers to the pattern in which a mineral breaks.
Hardness: It refers to what minerals it can scratch and what minerals can scratch it.
As we have discussed, a substance referred to as a mineral, which is a naturally occurring, inorganic, crystalline solid that has a characteristic chemical composition and crystal structure. The atoms in minerals are arranged in regular, repeating patterns that can be used to identify that particular mineral. It is classified on the basis of their chemical composition, and they are expressed in their physical properties. This module describes the classification of minerals the physical properties that are commonly used to identify minerals. They are colour, crystal form, hardness, density, luster, and cleavage. Also, we know how many types of minerals are there and their characteristics.