In reply to Timmd:
What do you mean by Cu mineral?
As is mentioned upthread, copper (Cu) can commonly be found in one of several oxidation states (0, +1, +2) which each has different speciation chemistry.
Elemental copper (copper on its own) is poorly soluble and has limited impact on solution pH so long as it retains its oxidation state.
Cupric (Cu2+) and cuprous (Cu+) copper ions are usually (but not always) associated/combined with other elements/molecules to make compounds - such as minerals. These behave quite differently to elemental copper and their properties depend on what the other elements/molecules involved are.
For instance, cuprous oxide (Cu2O) is more soluble than cupric oxide (CuO), whilst cuprous chloride (CuCl) is less soluble than cupric chloride (CuCl2).
Moreover, cupric oxide is mildly basic (upon dissolving in water it will increase the pH), whilst cupric chloride is a reasonably strong lewis acid (upon dissolving in water it will lower the pH).
Chemistry is complicated!
There are some simple rules of thumb though for copper/iron behaviour:
solubility is higher at low pH and lower at high pH (due to oxide/hydroxide formation)
dissolving oxide or hydroxide minerals will increase solution pH - whilst forming these minerals will reduce pH
dissolving other compounds such as chlorides or sulfates will reduce the pH
I hope this helps... I can send you some general references and/or solubility product constants tomorrow if you'd like.
Post edited at 23:54