Geologist blogger The World Complex has an interesting chart of global exploration expenditure by commodity, noting that “approximately 50% of all money spent on non-fuel mineral exploration during the last 15 years was spent on gold exploration” with copper being the second most important at around 20%.

Why such interest? It is not only because gold is so expensive, but also because of its [source: U.S. Geological Survey]:

• demand in aesthetic and technological applications
• profitability (in terms of revenue minus costs)
• widespread geological occurrence in relatively small deposits

Since we’ve only extracted around 170,000t of an estimated 390,000t of mineable gold, it looks like there are many more years for gold fever to continue.