Supply constraints have also played a part in the rising price because no significant new diamond deposits have been discovered in the past two decades.

With time, commodity prices will move back up again as supply constraints kick in, the result of cutbacks by the global miners.

Sound demographics and supply constraints still provide underpinning.

Oil prices, while volatile, have been generally high in this century because of that demand and because of supply constraints.

Recent electricity supply constraints and the reality that electricity tariffs are set to increase substantially have made the search for alternative sources of energy more urgent.