> Goldschmidt classification is nowhere near absolute, which is why we can have gold in the crust.

I thought that’s more to do with the following factors:

(1) chemical bonding subtleties mean that partition coefficients are never perfectly into exclusively one phase or the other

(2) core formation is far from a perfectly efficient process with regards to taking certain elements from other layers — even if partition coefficients were perfectly weighted to siderophile, reactions don’t run to completion without being diluted or interrupted, not least because the Earth was not completely molten for very long (if at all).

(3) the crust today (particularly the continental crust) has been modified extensively since whatever was left behind immediately after core formation. Transport and concentration of certain elements from the mantle to the crust and into more localised bits of the crust to form ore deposits has had ~4 billion years of geological processing to occur.

(4) most of the gold that exists in the crust today is thought to have been delivered to the Earth from space after core formation — the late veneer hypothesis eg. Dauphas & Marty, 2002

Is the Goldschmidt classification really so lacking? I know it was developed a long time ago but i thought it was only ever meant to be a broad classification scheme? Seems to fo a good job of that and it does allow for elements to have mixed classifications.