Platinum: the metal and the metaphor are associated with high privilege and outstanding performance.
Precious metals are classified as metals that are rare and/or have a high value. Platinum falls into both categories. It has a low natural abundance in the Earth’s crust and is most often found as a secondary component in deposits of nickel or copper. But unlike many metals that are typically found as compounds, such as copper sulfide, platinum is more often found in its elemental form in natural deposits.
Platinum’s grayish sheen has sometimes resulted in its being confused with silver, and it has gained great popularity in making jewelry since unlike silver, it does not tarnish. Platinum is different from white gold, which is usually gold alloyed with another element such as nickel, manganese, or palladium. Platinum is generally heavier and more durable than white gold, but it is also more expensive. The price of platinum is more prone to fluctuations than gold; in 2008 alone, the price ranged from $774 to over $2,200 per oz. From this information it is easy to see why credit cards labeled platinum status carry an imprimatur of status.
But by far the primary use of platinum is in the catalytic converters of automobiles. First used in catalytic converters in the mid-1970s, platinum processes unburned hydrocarbons from engine emissions into carbon dioxide and water before the exhaust exits the tailpipe. Since unburned hydrocarbons are a significant pollutant that causes photochemical smog and ground level ozone, catalytic converters play an important role in maintaining good air quality. It might seem odd that this precious metal would be used in cars, but platinum is so effective in relatively small quantities, that it is worth the cost. Or maybe, using platinum also reflects the value of clean air.
More information about platinum may be found at http://education.jlab.org/itselemental/ele078.html