The definition of a bubble is when an assets price has mindlessly exceeded even optimistic intrinsic valuation. For housing, it's when home are more expensive than the time adjusted value of all future cash flows (aka rent). For a stock, it's the time-adjusted value of the company's future earnings.

For gold, the intrinsic value is minuscule since it has almost no industrial application and it's value is rooted in senseless tradition and shininess. And yet gold continues to soar higher.

It's a bubble by definition.