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The word "mineral" is used to refer to two different kinds of components. One is the dietary minerals, and second is the elements formed due to geographical processes, simply called minerals.

A mineral is solid matter having a crystalline atomic or molecular structure. It is a homogeneous, naturally occurring substance with a clearly defined chemical composition. In 1965, the International Mineralogical Association adopted a standard definition for minerals as "an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes." Many minerals are used for extracting useful metals; and hence, it becomes important to study them thoroughly.

Minerals

There is an overwhelming number of known minerals. Currently, the International Mineralogical Association lists more than 4,600 minerals with new minerals still being discovered. Only 100 of these are common, while the rest are either encountered occasionally, or are very rare. With such a large number of minerals, it is difficult to identify and classify them separately. However, mineralogists identify minerals based on the following characteristics:
  • Streak
  • Luster
  • Sheen
  • Hardness
  • Cleavage
  • Crystal system/habit
  • Color
  • Specific Gravity
  • Clarity or Transparency
After the mineral has been identified and proven to be a mineral, it is classified as a silicate or non-silicate mineral, based on its composition.

Silicate Minerals
The most commonly found group of minerals in the Earth's crust is the silicate group. Almost all silicate minerals have silicon and oxygen as their base units. Most silicate minerals are formed by the cooling of molten rocks. As the molten rocks come closer to the surface inside the Earth's crust, they start cooling very fast and combine with the most abundant element in the Earth's crust -- silicon. Silicate minerals constitute approximately 90% of the Earth's crust. Mica, quartz, amazonites, olivine, and biotite are some of the examples of silicate minerals.

Non-silicate Minerals
There is a complete range of non-silicate minerals. Some of these are formed when there is cooling of magma, while some others are formed when water in them evaporates, or due to mineral decomposition. The non-silicates can be further classified into different groups which are:

Native Elements: Many pure elements that are found with a distinct mineral structure and occur naturally in an uncombined form, fall under this category. For example: uncombined carbon is often found in its pure state in the form of graphite or more rarely as diamond. Gold, silver, and sulfur are other elements, which are also found in their pure state. Even though these are pure elements, they qualify to be known as minerals, but no chemical process is required on them further.

Sulfides: This class of minerals have sulfide (S2−) as their basic unit. These inorganic compounds are sometimes as economically important as other ores. Some examples include Nickeline (NiAs), Pyrite (FeS2) and Molybdenite (MoS2).

Oxides: When an ore is found in which one or more elements are combined with oxygen, it is an oxide mineral. These may have chemical formulas of the type XO (MgO, ZnO, CuO, etc.), X2O (Cu2O), X2O3 (Al2O3, Fe2O3), XO2 (MnO2, SnO2) and XY2O4 (MgAl2O4, FeCr2O4). The oxide minerals are mostly of metallic elements. Example: hematite, magnetite, and cuprite. Silicates and oxides are the most common types of minerals in volcanoes, especially after an eruption.

Carbonates: This particular type is formed when a single carbonate ion (CO32-) reacts with a metal ion of complementing polarity. Example: siderite (FeCO3), smithsonite (ZnCO3), calcite (CaCO3). Carbonate minerals are used in making cement and other bonding material.

Sulfates: The mineral class which includes the sulfate ion (SO42-) within its molecular structure is categorized as a sulfate mineral. Minerals like Gypsum (CaSO4ยท2H2O) and Barite (BaSO4) are examples of sulfate minerals.

Organic Minerals: This class of minerals includes biogenic substances, genesis, or origin of which can be attributed to a geological process. Organic minerals include all types of oxalates, mellitates, citrates, cyanates, acetates, formates, hydrocarbons, etc. Examples of organic minerals include whewellite, moolooite, mellite, fichtelite, carpathite, evenkite, and abelsonite.

Apart from these, there are many more non-silicate minerals, like nitrates, sulfides, halides, phosphates, etc., but most of the 4,000-odd listed minerals are grouped in the above categories. Make sure you do not get confused between minerals and rocks. A rock is a combination of a number of minerals, which may also include organic remains and mineraloids, i.e., non-crystalline minerals.

Dietary Minerals

We know that there are four elements that are crucial for the existence of all living organisms. These are carbon, hydrogen, nitrogen, and oxygen. However, apart from these, there are certain chemical elements that are also required for sustainability of living organisms. These chemical elements are called dietary minerals. These dietary minerals are again divided into two groups based on their requirements.

Macrominerals
These minerals are required in large quantities, and their deficiency in the body can result in various ailments. However, excess of these minerals can also result in certain disorders.

Mineral Use Dietary Sources
Calcium
  • Building bones
  • Blood cell functions
  • Nerve and muscle functions
  • Dairy Products
  • Green leafy vegetables
  • Nuts and seeds
Chloride
  • Retaining water
  • Cheese
  • Lettuce and Tomato
  • Beef and Pork
  • Salt and Rye
Magnesium
  • Building bones
  • Nerve and muscle functions
  • Dairy Products
  • Green leafy vegetables
  • Nuts and seeds
  • Bran Cereal
  • Seafood
Phosphorus
  • Building bones
  • Energy storage
  • Dairy products
  • Fish
  • Poultry
  • Nuts and Peas
Potassium
  • Retaining
  • Nerve and muscle functions
  • Dried fruits
  • Citrus Fruits
  • Banana
  • Green Leafy Vegetables
Sodium
  • Retaining water
  • Nerve and muscle functions
  • Milk and Cheese
  • Beets, Celery, and Green olives
  • Beef and Pork
  • Salt

Trace Minerals
Our body requires these minerals in very small quantities. However, deficiency of these minerals can lead to health complications.

Mineral Use Dietary Sources
Copper
  • Protection from cell damage
  • Building bones
  • Producing red blood cells
  • Shellfish
  • Mushrooms
  • Chocolate
  • Nuts and Beans
Fluoride
  • Building bones
  • Tea
  • Saltwater fish
Iodine
  • Thyroid gland function
  • Seafood
  • Iodized Salt
Iron
  • Muscle function
  • Assists RBC to carry oxygen
  • Beef
  • Salmon and Tuna
  • Dried Fruits
  • Green Leafy Vegetables
  • Eggs
  • Potato baked with skin
Selenium
  • Thyroid gland function
  • Protection from cell damage
  • Fish and Shellfish
  • Chicken and Eggs
  • Red meat
  • Wheat germ
Zinc
  • Healthy skin
  • Strengthening immune system
  • Wound healing
  • Red meat
  • Legumes