Precious metals

A precious metal is more valuable for its rarity than for its physical use.

A rare metal, such as gold, is far too soft to be useful in much more than plating other metals, but is far more valuable than, for instance, iron, because it is harder to come by.

An interesting case of a precious metal going common is that of aluminum. Aluminum was, when it was first discovered, extremely difficult to separate from the rocks it was part of and, since the whole of the Earth's aluminum was bound up in the form of compounds, the most difficult metal on earth to get, despite the fact that it is one of the planet's most common.

For a while, precious aluminum was more valuable than gold, but the prices dropped continually and collapsed altogether when an easy extraction method was discovered in 1889.

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