Explain the different forms of occurrence …

Minerals are found in ores. Ore is defined as the accumulation of any mineral mixed with other elements. Minerals are found in various types. The types of minerals found are as follows:

• In metamorphic and igneous rocks, minerals are found in cracks, crevices and joints. Depending on the concentration they are classified into two types. The smaller one is called the veins and the larger one is called the lodes. They are formed when minerals in molten state/liquid state are forced upwards through the earth’s cavities. They solidify and form hard minerals. Example of this type is zinc, copper, lead etc.

• In sedimentary rocks, a number of minerals are found in bed or layers. They have been formed as a result of deposition, accumulation, and concentration in horizontal strata. Coal and some forms of iron ore are formed in this way. A group of sedimentary rocks like gypsum, potash salt and sodium salt are formed as a result of evaporation especially in the arid regions.

• Minerals like Bauxite are formed by weathering. It involves the decomposition of surface rocks and removal of soluble constituents leaving a residual mass.

• Minerals like alluvial deposits are found in the valley floor and base of the hills and are not corroded by water. Gold, silver, platinum are found in this way.

• The ocean floor is home to a large amount of magnesium nodules.