John Vertical wrote:
> This is just a rephrasing of the question, however. When does one use the
> adjectiv "molten", and when the participle "melted"? Oddly it seems
> materials described as "molten" are normally encounter'd in solid form
> ("molten quicksilver" seems redundant), 

Correct. Quicksilver, or 'mercury' as it's usually called nowadays, is 
sort of liquid in its normal state. In modern English IME 'molten' is 
used of minerals which are normally solid when they are very hot and in 
liquid state - whether this is mad-made, as in the processing of metals, 
or a natural occurrence when, for example, spewed out of a volcano.

> so an actual process of melting is required anyway. 

Yes - but it's an extreme melting - and, as I have observed, you'd use 
'molten' only adjectivally.

> But I don't recall seeing terms such as "molten butter"
> either. 

No - butter's not a mineral and, in any case, in hot weather it can be 
in quite a runny state without anyone having to apply more heat. Butter 
just gets melted    :)

> The observation that "molten" things are usually blazing hot I can
> agree with, but as an L2 English speaker, my intuition probably doesn't count.

I'd say it's got a lot going for it in this case - and if you add that 
"molten" things are (normally) mineral, you not likely to go seriously 
wrong IMO.

Frustra fit per plura quod potest
fieri per pauciora.
[William of Ockham]