Minerals are solid substances that have formed naturally in the Earth as crystals. Most rocks that we see today are made of minerals. There are over 3,000 known minerals. Some of the most common ones and their uses are:
- Graphite - the lead in a pencil
- Rock salt - used for cooking
- Gold - used in jewellery
- Marble – used for walls and fireplaces
- Quartz – the most common mineral in the rocks of the earth – used in clocks
Minerals are mostly formed at enormously high temperatures deep within the earth. Internal pressures and movements of the earth’s plates sometimes force rock upward through the surface of the earth as mountains or other landscapes. Some of these rocks contain important minerals that society might want. Individuals and companies often explore for these minerals, sometimes armed only with metal detectors and shovels, sometimes with large drilling equipment. GSI and other government departments provide maps and information on where minerals might be found. If minerals are found then it must be decided if they are plentiful enough to build a mine to recover them from the ground.
Some important minerals
Gold is a valuable, yellow metal. Gold is usually in metamorphic rock but sometimes is found in sedimentary ones, too. It is found in underground veins of rock where the inside of the Earth heats the water that flows through the rock.
Gold has been important all throughout history. For instance, we know that it was used at important events thousands of years ago in Egypt. We also know that people used it as jewellery way back in the Stone Age and even the Bible’s Old Testament has many references to Gold.
Gold has many uses. As well as jewellery, it is also very important as a form of money. This is because it has a very high value in the world and it can be used as a means to buy and sell things. Gold has also been used to make coins because it is a very durable substance – it stands up well to heat and moisture and other damaging elements. This also explains why it is used so successfully as jewellery. Gold is also used by dentists in some types of repair work and is used in the building of satellites and even in some medicines!
During the 19th century gold rushes occurred throughout the world. This was mainly because of the arrival of gold-seeking Europeans. America and Canada hosted some of the most famous gold-rushes at California, Colorado and Klondike. Old movies show cowboys panning for gold in the Wild West but did you know that Ireland also has some gold? Yes, many Irish Gold artefacts and objects are on display in the National Museum. In recent times Gold was discovered, or perhaps rediscovered, on the slopes of Croagh Patrick but it has not been mined primarily because of the mountain’s religious importance. Ireland’s first gold mine is now open near Omagh in Co. Tyrone and it is producing a range of Irish jewellery named Galántas. See www.galantas.com
Zinc is a blue-white metal that has many important uses. It is applied as a coat for iron and steel to prevent rusting. It is used in coins, medicines, vitamin tablets, deodorant and sun-cream. Indeed humans need zinc just to continue living – many of our bodies’ most important cells and proteins contain zinc. For instance we need zinc to see, taste, smell and remember properly.
Ireland has many zinc mines one of which in Navan is the largest in Europe. Indeed based on the amount of Zinc Ireland has discovered compared to our small size we are the world’s leading country. There are also large zinc mines in operation at Lisheen and Galmoy.
Gemstones are minerals or rocks that can be cut, shaped, and polished into beautiful stones that can be used in jewelry and for collecting. A stone is worth more money if it is perfect.
Most gemstones are minerals and have the same characteristics as minerals do. The weight of a gem is measured in carats (5 carats = 1 gram). Gems endure through time as they are resistant to chemical alteration, are sufficiently hard to retain a good polish and are not easily chipped or broken. Types of gem include emerald, ruby, jade and sapphire.
Diamond is named from the greek "adamas" meaning unconquerable as it is the hardest natural substance on Earth. In fact, they are so hard that the only things that will cut them are other diamonds. Diamond, like charcoal and graphite is a form of carbon. In fact, it is unique among gems as it is comprised of just one chemical - carbon. Diamond varies in colour from colourless to yellows, browns, greens, blues, pinks and a very rare red. Most are tinged with yellow or brown. The most prized are the rare red or rare colourless. Diamonds were known in India 2300 years ago.
Diamonds formed between 120-200 kms or 75-120 miles below the Earth's surface. Pockets of carbon dioxide existed deep beneath the Earth's crust. Over millions of years, extreme heat and pressure caused the carbon atoms to crystallize forming diamonds. Pressure built up causing volcanic eruptions that brought the diamonds up to the surface.
Whilst diamonds are a worldwide resource none are currently mined in Europe. Mining operations today exist in 25 countries with major production being dominated by Australia, Botswana, Russia, the Congo Republic and South Africa. Ireland has never commercially extracted diamonds although diamond exploration has occurred here, particularly in Donegal.
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