Question regarding Item colour W/B/P/G

Need some help on a question I was asked but couldnt answer...

Items drop in white, bule, purple or gold colours (not counting green at this point)

If you add a mod to a white item it becomes blue.. Is that the only colour change that can be done? or is it depending on the mod?

If I had a max damage purple item and added a max mod say 5-1 vampiric would/could it become gold??

Basically can a player change any other colours on weapons other than making the white (non-magic) to blue (magical)?

Thats it.. a bit silly I know but one I could not answer truthfully..
I could of course test this but trying lots of diff mods of diff levels on diff weapons could be rather costly... anyone clarify this pls..

I can answer this color changing question. I've added to blue items max value mods that would be gold in the Priest of Balthazar unlock screen. These items do not change color from blue.

I've also added max value mods to purple items, and they did not change color either.

But, having a White change to Blue makes sense. White items are ones with no mods on them, inate or otherwise. Blue+ are items of varying rarity that have mods on them, innate or otherwise.

Thanks v.much