Platinum is one of the most pure precious metals on the planet. It is seen mostly in high end engagement rings and other jewelry. The cost of an ounce of Platinum is Currently $1500 and is only going up.
Now what on earth does this have to do with cars?
Platinum is a vital component of the "Catalytic Converter" in your car. This converter takes the harmful emissions from your engine and makes them less harmful for the environment.
Now while this is all good stuff there is one bad side to having a Catalytic Converter in your car. People steal these parts to your car, it isn't so common anymore mostly because car companies have made it more difficult to get to them and there is too little metal in there to make it worthwhile. However, if you ever notice your car has gotten louder you may want to have it checked out by a professional mechanic just to make sure nothing is missing.
If you want to know more about Catalytic Converters and the metal inside, click on the link in the second paragraph or go to howstuffworks.com.