- A naturally occurring substance that has a definite chemical composition is a mineral.
- A rock is an aggregate of one or more minerals but without definite composition of constituent of mineral. Rocks from which minerals are mined are known as ores.
- On the basis of composition, minerals are classified mainly as metallic and non-metallic minerals.
- Metallic minerals contain metal in raw form. Metals are hard substances that conduct heat and electricity and have a characteristic lustre or shine. Iron ore, bauxite, manganese ore are some examples.
- Metallic minerals may be ferrous or non-ferrous.
- Ferrous minerals like iron ore, manganese and chromites contain iron. A non-ferrous mineral does not contain iron but may contain some other metal such as gold, silver, copper or lead.
- Non-metallic minerals do not contain metals. Limestone, mica and gypsum are examples of such minerals.
- The mineral fuels like coal and petroleum are also non-metallic minerals.
- Minerals can be extracted by mining, drilling or quarrying.
-The process of taking out minerals from rocks buried under the earth’s surface is called mining.
- Minerals that lie at shallow depths are taken out by removing the surface layer; this is known asopen-cast mining.
- Deep bores, called shafts, have to be made to reach mineral deposits that lie at great depths. This is called shaft mining. Petroleum and natural gas occur far below the earth’s surface. Deep wells are bored to take them out, this is called drilling.
- Minerals that lie near the surface are simply dug out, by the process known as quarrying.
- If a rock contains copper then the rock looks blue in colour.
- Generally, metallic minerals are found in igneous and metamorphic rock formations that form large plateaus. Iron-ore in north Sweden, copper and nickel deposits in Ontario, Canada, iron, nickel, chromites and platinum in South Africa are examples of minerals found in igneous and metamorphic rocks.
- Sedimentary rock formations of plains and young fold mountains contain non-metallic minerals like limestone. Limestone deposits of Caucasus region of France, manganese deposits of Georgia and Ukraine and phosphate beds of Algeria are some examples.
- China and India have large iron ore deposits.
- China, Malaysia and Indonesia are among the world’s leading tin producers.
- China also leads in production of lead, antimony and tungsten. - Europe is the leading producer of iron-ore in the world.
- The countries with large deposits of iron ore are Russia, Ukraine, Sweden and France.
- Switzerland has no known mineral deposit in it.
- The mineral deposits in North America are located in three zones: the Canadian region north of the Great Lakes, the Appalachian region and the mountain ranges of the west.
- Iron ore, nickel, gold, uranium and copper are mined in the Canadian Shield Region, coal in the Appalachians region.
- Western Cordilleras have vast deposits of copper, lead, zinc, gold and silver.
- Brazil is the largest producer of high grade iron-ore in the world.
- Chile and Peru are leading producers of copper.
- Brazil and Bolivia are among the world’s largest producers of tin
- Africa is the world’s largest producer of diamonds, gold and platinum. - South Africa, Zimbabwe and Zaire produce a large portion of the world’s gold.
- Australia is the largest producer of bauxite in the world.
- Kalgoorlie and Coolgardie areas of western Australia have the largest deposits of gold.
- India is the largest producer and exporter of mica in the world.
- Kolar in Karnataka has deposits of gold in India.
- Major limestone producing states in India are Bihar, Jharkhand, Odisha, Madhya Pradesh, Chhattisgarh, Rajasthan, Gujarat and Tamil Nadu
- Silicon, used in the computer industry is obtained from quartz.
- Aluminum obtained from its ore bauxite is used in automobiles and airplanes, bottling industry, buildings and even in kitchen cookware.
- The oldest rocks in the world are in Western Australia.
- A green diamond is the rarest diamond.
- Firewood and fossil fuels are the two main conventional energy sources.
- Electricity from coal is called thermal power.
- Coal is referred to as Buried Sunshine.
- The coal producing areas of India are Raniganj, Jharia, Dhanbad and Bokaro in Jharkhand.
- Petroleum and its derivatives are called Black Gold.
- Compressed natural gas (CNG) is a popular ecofriendly automobile fuel as it causes less pollution than petroleum and diesel.
- Natural gas is found with petroleum deposits and is released when crude oil is brought to the surface.
- Russia, Norway, UK and the Netherlands are the major producers of natural gas.
- In India Jaisalmer, Krishna Godavari delta, Tripura and some areas off shore in Mumbai have natural gas resources.
- Norway was the first country in the world to devlop hydroelectricity.
- Some important hydel power stations in India are Bhakra Nangal, Gandhi Sagar, Nagarjunsagar and Damodar valley projects.
- Non-conventional sources such as solar energy, wind energy, tidal energy are renewable.
- In India Rajasthan and Jharkhand have large deposits of Uranium.
- Thorium is found in large quantities in the Monozite sands of Kerala. - Heat energy obtained from the earth is called geothermal energy.
- USA has the world’s largest geothermal power plants followed by New Zealand, Iceland, Philippines and Central America.
- In India, geothermal plants are located in Manikaran in Himachal Pradesh and Puga Valley in Ladakh.
- The first tidal energy station was built in France.
- Russia, France and the Gulf of Kachchh in India have huge tidal mill farms.
- Organic waste such as dead plant and animal material, animal dung and kitchen waste can be converted into a gaseous fuel called biogas.
- The organic waste is decomposed by bacteria in biogas digesters to emit biogas which is essentially a mixture of methane and carbon dioxide.