Is Gold a Bubble?

Is gold a bubble? Although prices have certainly risen recently, it is difficult to tell. By comparing the rise of gold recently to bubbles in the past, we can get a better handle on the nature of the recent uptick.

As you can see, gold has steadily risen over the past 70 months. Nominally the rise is almost identical to the rise of gold in 1980, but there has not yet been a clear inflection point where the price rises extremely fast (perhaps the defining characteristic of a bubble).

Is it a bubble? What do you think?