Classification of Minerals
Minerals can be separated into two main categories, namely, main elements (calcium, potassium, phosphorous, chlorine, sodium, magnesium) and trace elements (iron, zinc, copper, manganese and iodine etc). According to their biological roles, they may also be separated into essential elements that have called as biological roles; non-essential elements with unknown functions; and toxic elements. There are 20 necessary nutritive elements e.g. sodium, potassium, phosphorous, iron, calcium, chromium, zinc, selenium, magnesium, copper, tin, cobalt, manganese and fluorine. Non nutritive non toxic elements are boron and aluminium; and non nutritive, toxic elements are mercury, lead and cadmium