All cool, cool, cool. Thank you both.

FF was silver in the movies but gold in the books.

No, Liquid luck was more of a golden-amber color it was like that in the movies too

No in the movie it was most definitely silver.

It changed color in the movies

Are you sure that's from the movies?

These are actually from the movies.

This one is also from the movies but its probably just the light. Plus it looks more clear in the movies not so much sliver or mercury like

Hmm, I was just looking at this page- Unicorn blood and extracted memories are silvery liquids, but they're not exactly potions so I'm not sure if that helps

Ooh, unicorn blood might work...

Full disclosure: I have this silvery looking liquid left over from a project and am thinking of bottling it up and labelling it for my Harry Potter display.