Above Title: The Mineral Bismuth (Image Black & White)
Above: Some images of minerals and a model of the structure of a mineral.
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Rocks commonly consist of several minerals composed of compounds of many elements, some essential, some accessory. There are only a handful of rocks made of just one type of mineral. The same is for minerals, as only some made up of a single element. Each rock is formed under certain conditions, resulting in its unique formation along with a fairly predictable group of minerals. This is because a mineral can only stay the same over a long period of time if the conditions it was exposed to when it formed do not change. Changes in pressure, the temperature of even pH levels in groundwater can trigger a change, as minerals become unstable and alter their chemistry forming a new mineral. It is this reason that means that new minerals will always be discovered. Minerals form inside Earth's crust, mines, and volcanoes and on the Earth's surface. They form either through the crystallisation of magma or the crystallisation of materials dissolved in water.
Minerals are naturally occurring chemical compounds. Minerals exhibit specific characteristics. Some can be fluorescent, as their electrons react under an ultraviolent (UV) light, while others can be radioactive ☢ because they contain elements and/or minerals that are radioactive, such as uranium. Minerals in solid state form crystals. Most minerals consist of two parts - metal ions and non-metal ions. Minerals are structured with their atoms arranged in a regular way. A mineral can scratch or mark a softer mineral, but not a harder mineral. Diamonds are the hardest mineral known to exist. The density is determined by a mineral's structure and chemical composition. It's when a sample is picked up and feels heavy or light for its size. Minerals are classified according to their composition and crystal size. They are put together in the groups and families of the same non-metal ion and they can also by categorised into their chemical group. |