Our Earth consists of over 49,000 different minerals, which are defined as substances having unique properties and chemical representations. They are usually naturally occurring, crystalline and stable at room temperature. An element or chemical compound is termed a mineral when its formation includes geological processes and thus minerals may include biogenic substances. Minerals can be classified in different ways some of which include physical properties, chemical analysis and optical analysis and X-ray diffraction. However other than classification by physical characteristics such as crystal structure, hardness, lustre, colour and streak, tenacity, specific gravity, the other methods of classification are time-consuming and expensive. Some minerals are found abundantly on earth while some occur very rarely. Here are the top ten minerals that are found abundantly on earth.
Amphibole is a mineral consisting of iron and/or magnesium ions. It is generally dark coloured and form prism or needle shaped crystals. Amphiboles may be colourless or may be green, black, white, yellow, blue or brown in colour. Amphiboles occur in igneous or metamorphic rocks such as granite, diorite and andesite. Amphibole is very hard and can be highly polished. Thus it is used as a dimension stone in construction. It is used as paving stones, veneer and facing in structures. Crushed stone amphiboles are used in road and railroad bed construction. Due to the shimmer effect when it is polished it is also used in making jewellery.
Pyroxene is an important rock forming mineral occurring in igneous and metamorphic rocks. It consists of ions of calcium, sodium, iron, magnesium, zinc, manganese, lithium, chromium, aluminium, scandium, titanium, vanadium. The origins of the name pyroxene are the Greek words for fire and stranger. Present in volcanic lavas, they sometimes occur as crystals embedded in volcanic glass and are often assumed as impurities in the glass. Thus they were named ‘fire strangers’. It is an important and large component of the earth’s mantle. Pyroxenes are used to manufacture salts and glasses. It is also used to manufacture jade.
Haematite derives its name from the Greek word for blood ‘haima’ as it can be red in colour. It is the mineral form of ferric oxide. Haematite is black, silver grey, steel, brown, reddish brown or red in colour. Haematite is found in banded iron formations. It is present in rouge and makeup polish due to its red pigment. It is mined as the main ore of iron which is used to make steel tools, bolts, nails, machinery and build bridges and other structures. Black coloured Haematite is sometimes known as black diamond. It is used in ornamental jewellery due to its attractive earthy tones. Haematite was used in making war paint by Ancient Romans who believed that it would make them invincible.
Magnetite is the mineral form of ferrous-ferric oxide. Magnetite occurs in igneous and metamorphic rocks and is black or brownish black in colour with a metallic lustre. Lodestone, which are magnetized pieces of magnetite attract pieces of iron and exhibit magnetism properties. Magnetite is used to make the magnetic layer in floppy disks, hard disks and cassette tapes. It also acts as a catalyst in the production of industrial ammonia. Magnetite is used for coating industrial water tube steam boilers due to its stability at high temperatures. It can also act as a sorbent in purifying arsenic contaminated water.
Calcite is the mineral form of calcium carbonate. It is a common mineral and occurs in igneous, sedimentary and metamorphic rocks all over the world. Calcite is the main constituent of limestone and marble which are found everywhere and make up a large part of the earth’s crust. They act as one of the largest carbon repositories of the earth. Calcite has many uses in various industrial sectors. Calcite is used in construction in the form of limestone and marble which are used in monuments, statues and other fine architecture. Limestone and marble are also used to produce cement and concrete which are durable construction materials. Calcite is used in agriculture as an acid-neutralizing soil treatment in the form of crushed marble and limestone. Crushed limestone is also used to neutralize acid mine drainage in water streams. Calcite derived from highly pure limestone or marble is used in medicines for neutralization of stomach acids. It can also be used as a solvent for pollutants produced in the process of burning fossil fuels. Calcite is also used in whitewash and as dietary supplements of animals.
Biotite is a mineral within the mica group, often known as ‘black mica’. It consists of magnesium, iron, silicon, aluminium, hydrogen and oxygen sheets bound together weakly by ions of potassium. Biotite is flaky in nature and resembles a book with many pages of sheets when found in large chunks. It can be greenish to brown to black in colour. It may also appear yellow when weathered. Biotite occurs in almost all the igneous and metamorphic rocks. Biotite is known as ‘Fool’s Gold’ as it causes reflections when struck by sunlight and is mistakenly assumed gold by first time gold panners. Biotite has a limited number of industrial uses. It is used as an extender and filler in paints and an additive to drilling mud. It is also used commercially as an inert filler and mould-release in the rubber industry. Biotite is also used to date igneous rocks.
Muscovite is a mineral of the mica group consisting of aluminium and potassium. It is also known as white mica, isinglass and potash mica. Muscovite derives its name from Muscovy-glass, the name given to the mineral in Elizabethan England in the sixteenth century as they came to know of its use in medieval Russia as a cheaper alternative to the glass in windows. It is the most common mica present in igneous, metamorphic and sedimentary rocks. It is an important rock forming mineral having a vitreous to pearly lustre on its sheets. It appears transparent and nearly colourless when held to light, having a slight brown, yellow, green or rose tint. Sheet muscovite acts as an excellent insulator in specialized parts of electrical equipment. Flaked, ground or scrap muscovite act as fillers and extenders in a variety of manufactured products, paints and surface treatments. It is an important ingredient that adds glitter to cosmetics, paints and ceramic glazes due to its sometimes pearly lustre.
Olivine is the mineral form of magnesium iron silicate consisting of oxygen, silicon, magnesium, iron, manganese and nickel. It occurs in a large quantity in the earth’s subsurface but weathers quickly on the surface. It is pale olive green to yellow-green and may be occasionally brown in colour. It has a translucent lustre and is harder than glass. Olivine is only found in igneous rocks in divergent plate boundaries and oceanic hot-spots. The ancient Egyptians used the gemstone peridot, a mineral in the olivine series as jewellery. Peridot has a pale yellow-green colour and is known as evening emerald, rumoured to be one of Cleopatra’s favourite gemstones. Olivine is used industrially as abrasives and decorative building stones. It is also used as refractory sand in steel manufacturing.
Quartz is the mineral form of silicon-oxygen tetrahedra. It is the second most abundant mineral occurring in the earth’s continental crust. Present in igneous, sedimentary, and metamorphic rocks, quartz has different varieties, several of which are gemstones used in making jewellery. It may be clear, white, gray, purple, yellow, brown, black, pink, green, red. It is durable, hard and chemically inert with other substances and is thus used as an abrasive and foundry sand. It has electrical and heat resistance properties and is thus used in manufacturing electrical products. Quartz sand is used in making different varieties of glass. Quartz sand is used in the petroleum industry and as a filler in the manufacture of rubber and paint.
Feldspar is the most abundant mineral found on earth and constitutes about 60 percent of the earth’s crust. Feldspar is generally pale in colour and may be white, pink, tan, green or gray. Feldspar occurs in igneous and metamorphic rocks and has many industrial uses. It is used in the glass and ceramic industries as a flux. It is used in the manufacture of dinnerware, bathroom and building tiles. It is used in making cement, concrete, pottery, enamelware, soaps, abrasive wheels, insulating compositions, tarred roofing materials and as fillers in textile or paper. In agriculture it is used as a fertilizer and poultry grit.