The intrinsic value of gold is set by manufacturing and jewelry; it has not changed much. The investment value of gold is (primarily) set by two things: the need for an inflation hedge, and speculation. Speculation is pretty much dead at the moment (nobody's buying gold because they think gold is going to go up). And gold's use as an inflation hedge is declining, because people are less worried about inflation than they were.

Why were people more worried about inflation recently? Because they thought that QE was going to cause a ton of inflation. As it now looks like the Fed will be able to unwind all of that without triggering mass inflation, people see less need for gold than they did, say, five years ago.