The chemistry that causes dull grey patination is the same as what produces the beautiful colours seen here.
What IS different is the thickness of the patination.
There a a phsical analogy with oil on water.
If the layer of oil is only molecules thick, a colour interference in the reflected light on the surface happens.
I suspect that the same sort of thing is happening with the very thin oxide and sulphide layers on metal surface.
What IS different is the thickness of the patination.
There a a phsical analogy with oil on water.
If the layer of oil is only molecules thick, a colour interference in the reflected light on the surface happens.
I suspect that the same sort of thing is happening with the very thin oxide and sulphide layers on metal surface.











Sorry for the bad picture quality









