How did copper sulphate come to be known as "blue vitriol"; ferrous sulphate as "green vitriol"; zinc sulphate as "white vitriol" and sulphuric acid as "oil of vitriol" ?

 

I get the colour part in the salt names, but why the "vitriol" ? Does that mean sulphate ?

Yes, vitriol means sulf!

Is it latin/greek or just some old english name ?

Look: Middle English, from Old French, from Medieval Latin vitriolum, from Late Latin vitreolum, neuter of vitreolus, of glass, from Latin vitreus. See vitreous.

 

So its latin!

What about "aqua reggia" ? Where does that come from ? What does it mean ?

"Royal Water" or something like that. Latin, I think.

I get the colour part in the salt names, but why the "vitriol" ? Does that mean sulphate ?

 

Note that the "vitriol" names likely came first, before much was known about the chemistry details.

Note that the "vitriol" names likely came first, before much was known about the chemistry details.

 

All four being sulphates, could it be then because on reaction with oil of vitriol metals produced these coloured vitriols ?

basicly yes, they used a more descriptive if not floral names for such chems, then came along a better understanding, and thus a newer "more descriptive" but less "floral" naming for them