(I) the natural material in which the metals or their compound as are found in the earth are called minerals.different mineral contain verying percentage of metal .minerals may not contain objectionable impurities which hamper the extraction of metals.
(ii) those minnerals from which the metals can be extracted conveniently and profitably are called ore . An ore contain a good percentage of metals and there are no objectionable impurities in it.
(iii) the ore mined from from the earth are usually with a large number of impurities .the unwanted impurities like sand, rocky minerals ,earthy particles ,limestone,mica,etc. Present in an ore are called gangue.