|Source: U.S. Department of Interior|
"Rhenium is a very rare metal and is commonly found as a trace metal in Molybdenum and copper ores. Its concentration is something less than 5 parts per billion. To put some perspective on it, Gold is estimated to be .005 parts per million." - www.rheniumsource.comI'm pretty sure 5 parts per billion is the same as .005 parts per million. (Divide each pair and compare the results).
In any case, Rhenium is about as scarce as Gold, and it's price is likewise floating around up there in the stratosphere. The same article explains the recent drop in price:
"Capacity for the production of Re has increased in the world, particular after the price escalation in 2008. It was speculation that the market was going to continue to grow but investors were caught of guard with the finicky nature of demand in aerospace."