Various metals in Aqua Regia - will they dissolve?

[Marcel]

Found it kind of interesting to see a large number of metals in AR and how they react.
I would have preferred to have some metals shown individually and not mixed with others (some cementing is visible in these cases). Also using metallic pliers is not ideal.
But other than that it may be helpful for some mystery metal experiments.....

 

[Deano]

There exists a phenomenon called contact passivation where metals and ores which are in direct contact with each other will solubilise in the order of their position on the EMF series.
This means that a mixture of metals can have multiple contacts with other metals and will dissolve in the EMF series order for which ever leachant is being used.
You would need an EMF series for various aqua regia ratios at various temperatures on various metals to cover just some of the possibilities you might test for with various metals.
If you do not have actual metal contact then the dissolution will occur as per tables of metal reactions in aqua regia.
Deano