A barrel of crude oil is a “hard asset.” Even if you are not in the oil business, you can trade barrels of crude oil in markets for the exchange of commodities. But the value of crude oil is not intrinsic. A few hundred years ago, before the invention of engines that could use oil as fuel, the value of crude oil was zero. Some day, if solar power becomes cheap enough, the value of crude oil may once again be close to zero. Meanwhile, the price of crude fluctuates, depending on the current state of supply and demand as well as expectations for supply and demand conditions in the future.