Geology is a science of general tendencies with frequent exceptions, not one of hard and fast rules that are always true and never vary. For almost every well-accepted rule of gold deposits, I can point you to a number of important exceptions.

Palladium may well be an underexplored element and therefore an opportunity for prospectors and geologists. This is because they are often less than obvious and other than the native metals, a chemical analysis of samples is required to identify PGM-enriched rocks.