The metal is expensive, not because it is rare but because of the expense to produce and work it. The minerals mined for titanium are all oxides, unlike many base metals that are mostly mined as sulfide minerals.

Gold is a fairly widespread mineral in the Italian Alps and in the Northern Apennines. It is found both in primary mineralization and in past and recent floods.

The old timers typically washed these areas down to bedrock, and some areas appear terraced. I would imagine this is because these hydraulic mines were generally where the miners found old Tertiary river channels on the sides of mountains that were gold-bearing.