Most Rocks are Made Up of Several Different Minerals
A mineral in geology terms is an inorganic solid which has occurred naturally through a geological process. It must have a specific chemical composition and distinctive internal crystal structure. Something that's inorganic cannot contain any living matter. So to be correctly described as a mineral a naturally occurring solid must be made up of crystals.
Minerals are made up of ninety two different elements. Elements which are made up of atoms are chemically the simplest substances which means they cannot be broken down through a chemical reaction. A chemical reaction causes a substance to change into one or more different substances.
Although minerals can be made up of one single element the vast majority are made up of at least two. Those made up of one are known as native elements and include copper, aluminium, carbon, iron, lead, vanadium and silver to name just a few. When a substance is made up of two or more chemical elements it becomes known as a chemical compound.
The word crystalline is used to describe a naturally occurring solid that has a crystal structure so something described as being crystalline (being made up of crystals) is a mineral. A crystal structure is an arrangement of atoms that come together in a highly ordered three-dimensional pattern to form a solid body known as a crystal.
Naturally occurring solids that do not have a significant crystal structure cannot be classified as minerals and are instead known as mineraloids. Some of the best known mineraloids include amber which is fossilised tree resin, shungite, moldavite, opal, pearl and obsidian which is volcanic glass.
Most of the rocks on our planet are made up of several different minerals but some such as calcite and quartzite are made up primarily of one single mineral.
Although there are close to 4000 minerals which have been identified only about 100 are classified as being common. Whilst identifying a mineral can sometimes be quite straightforward it can also be extremely difficult. Colour is usually a good place to start but can be the most unreliable method because many minerals occur in a variety of different colours.
Streak and lustre may also be used for identification purposes. Streak is the term used to describe the colour of a mineral in powdered form, it never changes and is not always the same colour as the mineral itself. Lustre describes the way light interacts with the surface of a mineral.
Almost everything around us is made up of minerals. The metals in household appliances and cookware, the materials used to produce tableware, copper wiring and pipes, graphite in pencils, talcum powder, cosmetics, the pigments in paints and even mobile phones and computers which are made of many different minerals. The materials used in the production of roads and pavements, the soil additives used in agriculture and of course not forgetting the most obvious minerals such as gold, silver and gemstones.
When used from a nutritional perspective the word mineral has a slightly different meaning. Minerals are required in small amounts to enable our bodies to function normally. Different amounts are needed by different people depending on age, sex and overall health. Some of the most important minerals for the human body include magnesium, sodium, calcium, potassium, iron, zinc, fluoride, selenium, manganese and chromium to name just a few.