Harmonium being a universal metalmind?

[I think I am here.]

I don't know if this has been said before.

Lerasium acts much like a 'catch-all' for Allomancy, granting all Allomantic powers. Atium acts much like a 'catch-all' for Hemalurgy, being able to steal any attribute. Therefore, shouldn't Harmonium act similarly?

Lerasium is of Preservation, like Allomancy. Atium is of Ruin, like Hemalurgy. Feruchemy is a mix, an end-neutral system. Which closely relates to Harmony, a mix of Ruin and Preservation. Since each god metal acts as a universal metal for its relative Shard's metallic art, shouldn't Harmonium therefore be a universal Feruchemical metalmind?

The only problem I can see is that why wouldn't the Southern Scadrians notice it's ability if it really did act like I say?

But there's definitely something going on with Harmonium and at least Feruchemic mechanics. Such as when Allomancers use the primer cube, they are practically storing their Allomantic output into the metal, which then automatically 'taps' it, giving off the Allomantic effect.

[Quantus]

I dont personally think so, but it's always possible.  Feruchemy predates the merger of the two into Harmony, and while it formed because of the presence of two shard is still a Preservation thing (per This and This).  Harmonium, by contrast is a much more direct embodiment of the warring nature of those two shards being held by a single vessel, which is why it is so volatile.  So volatile, it cannot physically be used for either Allomancy or Hemalurgy, since the former requires that you ingest it and the latter requires that it contact your Blood, and in either case it would explode like an alkali metal