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 water bath. Platinum is also non-magnetic, while nickel and iron are both magnetic. 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, while 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.
This Iris brooch with yellow sapphires, tsavorites and diamonds in platinum is valued $38,000. Let we have a look at the specification of this elegant and captivating brooch in platinum with yellow sapphires, tsavorites, round brilliant diamonds and 18k gold. Yellow sapphires, carat total weight 20.06; tsavorites, carat total weight .81; round brilliant diamonds, carat total weight .60.