its just an opinion but I never minded the kamino sequences, plus jango as a character is pretty cool, a scientific explanation is the way to go, i like the mineral idea, something that requires the humidity of the planet to form perhaps

so the droids could say something along the lines of

' the intermetallic alloy has been identified as a rare combination of elements formed under high pressure and consistently very high humidity, the only known region that could sustain this type of chemical reaction is the planet kamino