 If pure platinum is found in placer deposits or other ores , it is isolated from them by various methods of subtracting impurities . Because platinum is significantly denser than many of its impurities , the lighter impurities can be removed by simply floating them away in a liquid . Platinum is paramagnetic , whereas nickel and iron are both ferromagnetic . These two impurities are thus removed by running an electromagnet over the mixture . Because platinum has a higher melting point than most other substances , many impurities can be burned or melted away without melting the platinum . Finally , platinum is resistant to hydrochloric and sulfuric acids , whereas other substances are readily attacked by them . Metal impurities can be removed by stirring the mixture in either of the two acids and recovering the remaining platinum . 
