Duralumin is an alloy of aluminium with some other metals. It is made up of 90% aluminium 4% copper 1% magnesium and 1% manganese. As it is a light and hard it is used in aircraft construction.

Coal is classified into four types based on carbon content.
They are:
1. Anthracite
2. Bituminous
3. Lignite
4. Peat.

India, China, Japan, Italy and States of America are major utilizers of solar energy in the world.

(i) Iron is used to manufacture steel and also used in civil engineering like reinforced concrete, girders etc.
(ii) It is used to make alloy steels like carbon steels with additives such as nickel, chromium, vanadium, tungsten and manganese.

Anything which can be used for satisfying the human needs is called resource. Natural resources are resources that exist without action of humankind.

Fossil fuel resources:
(i) Fossil fuel resources are normally formed from the remains of dead plants and animals. 
(ii) They are often referred to as fossil fuels and are formed from hydrocarbon.
Coal:
(i) This is the most abundantly found fossil fuel that forms when dead plant matter is converted into peat.
(ii) It is used as a domestic fuel, in industries such as iron and steel, steam engines to generate electricity.
Petroleum:
(i) Petroleum is found between the layers of rocks and is drilled from oil fields located in Offshore and coastal areas.
(ii) Petroleum and its derivative are called Black Gold as they are very valuable.
Natural gas:
(i) Natural gas is found with petroleum deposits and is released when crude oil is brought to the surface.
(ii) It can be used as a domestic and industrial fuel.

Non-metallic resources:
(i) Non-metallic resources can be described as the resources that do not comprise of metals.
(ii) These are not hard substances, and are not good conductors of heat and electricity.
(iii) Example for non-metallic resources are mica, limestone, gypsum, dolomite, phosphate, etc.
Mica:
(i) Muscovite and Biotite are the common ores of Mica.
(ii) It is one of the indispensable minerals used in electrical and electronics industry.
(iii) In powder form, it is used for making lubricating oils and decorative wallpapers.
Limestone :
(i) Limestone is a sedimentary rock, composed mainly by skeletal fragments of marine organisms such as coral, foraminifera and molluscs.
(ii) About 10 % of sedimentary rocks are limestones. Mostly limestone is made into crushed stone and used as a construction material.
(iii) It is used for facing stone, floor tiles, stair treads, windows sills and many other purposes.
(iv) Crushed limestone is used in smelting and other metal refining process. Portland cement is made from limestone.

Solar energy:
(i) The sun produces energy in the form of heat and light. Solar energy is not harmful to the environment.
(ii) Photovoltaic devices or solar cells, directly convert solar energy into electricity.
(iii) India, China, Japan, Italy and States of America are major utilizers of solar energy in the world.
Hydropower:
(i) Hydroelectricity power is the cheapest and most versatile source of energy out of all the known energy. Hydroelectric power is a renewable resource.
(ii) China, Canada, Brazil, United States of America, Russia, India, Norway and Japan are some countries producing hydroelectricity. China is the largest producer of hydroelectricity.
Wind energy:
(i) Wind power is clean energy since wind turbines does not produce any emission.
(ii) In recent years, wind energy has become one of the most economical and renewable energy technologies.
(iii) Major wind energy producing countries are United States, China, Germany, Spain, India, United Kingdom, Canada and Brazil.