Organic and inorganic substances; saving natural resources

Substances obtained from living organisms are called organic: wood, paper, wool, honey, vegetable oil, cotton. Substances formed without living organisms are inorganic: iron, gold, diamond, stone, salt. The Earth’s crust consists of rocks. Granite is very strong and used for bridge foundations and statues; marble is beautiful and decorates building walls; clay becomes soft when wet and is used for pots and bricks. Rocks are mixtures of minerals (for example granite contains quartz, feldspar and mica). Jewellery uses minerals such as amethyst, sapphire and emerald. Oil and coal are organic minerals: they formed from the remains of living things that lived millions of years ago. From oil we get petrol, kerosene, fuel oil, plastic and tyres.