One factor holding the metal back, he said, are some of the recent losses in other markets, such as equities and other commodities.

FORBES: Gold Strong In Euro Terms But Faces Offsetting Factors Against Dollar

Spiegel speculate that as the baby boomer generation ages, they are likely to shift from buying stocks to selling their equity holdings to finance retirement, and this shift could be a factor holding down equity valuations over the next two decades.

FORBES: The Great Age-Wave Ruse

"As well as being careful to find a system that works unfailingly, be it fingerprints or eye scans, the main factor holding back airlines from introducing more biometric systems is the lack of integration, " a spokesperson for British Airways told CNN.

CNN: Heathrow tests biometrics