How to find color veins

[HKK]

Hey everyone.

Meh, after a long while I thought I'd start this game again. Now I'm at the part where you have to break open the color veins in the mines, but I forgot how to find them. I remember the last time I played, I could see them shimmering through (like in the intro-video for the Expose glyph), but now I can't see anything.
Was there another Glyph involved for finding the veins (if so, where do I get it) ?

Thanks in advance,
~HKK