Idioms, Fallacies, and Paradoxes

Paradox of Value

Also referred to as "diamond-water paradox." Water is more useful than diamonds, yet is a lot cheaper.

The apparent contradiction that, although water is on the whole more useful, in terms of survival, than diamonds, diamonds command a higher price in the market. 

The observation that articles or goods critical to life are very cheap, whereas others which have no bearing on human existence are very expensive.

This paradox can be explained by the law of supply and demands.