Actually this is a coursework that I am working on, that is the study of the platinum group metals commodity in relation to the market demand and supply. The history of such metals is actually very very short, just slightly over 200 years for most metals and platinum has only slightly longer history than the rest. Here is a good site to read some history:
http://www.stillwaterpalladium.com/history.htmlAs you can see, it was actually the Spanish colonization of South America that they made the discovery. Word got out that there is a type of silver that couldn't be melted down by normal means and it was an unwanted metal product. Silly enough though, if you read how the word platinum was formed, it was a degotory form of the native S. American word for "little silver"
As soon as when people in Europe knew about this unwanted metal as well as it's density heavier than gold, people smuggled out this metal as price of gold if I am not mistaken was at least 150% more than platinum at any stage and therefore it was profitable to have an alloy of platinum and gold plate it. From what I have seen, Spain, France, UK all had issues with such gold plated platinum coins and Russia was the only exception that dared to have legal platinum coinages for circulation. The only problem was, people's perception of such platinum coins were awfully bad and therefore they didn't last too long. If I am not mistaken, the US did have a dollar coin around that era that was trial struck in platinum as well.
In today's story though, such gold plated platinum coins actually do hold quite a fair bit of value - that is if you can even find one in the first place. Trust me, they are HARD to find and I'm even having issues trying to find a proper reference at the moment.