(a) "Minerals occur in igneous and metamorphic rocks." Explain the statement with example.

(i) Minerals may occur in the cracks, crevices, faults or joints.

(ii) The smaller occurrences are called veins and the larger are called lodes.

(iii)In most cases they are formed when minerals in liquid/molten and gaseous forms are forced upward through cavities towards the earth’s surface. Eg, tin, copper, zinc and lead.

(b) “The ocean water contains vast quantities of minerals.” Explain the statement with example.

(i) Most of the minerals are too widely diffused to be of economic significance.

(ii) Common salt, magnesium and bromine are largely derived from ocean water.

(iii) The ocean beds, too, are rich in manganese nodules