How do I get the runes in Normal difficulty?

In Shadowgate (2014), I'm in the Shadowgate castle on Normal difficulty (i.e. the easiest one without the time limit), and I'm afraid I'm stuck. When I ask Yorick for hints, he says this:

The wizards would not have placed so many powerful runes in the castle if they did not have some greater purpose. Perhaps you should take them for yourself.

I see that, for instance, the Empty Room, after dispelling the illusion with the Flumoris spell, has a rune that has an eagle on it. But when I try to take it, I get the following:

You struggle to get ahold of the rune, but it doesn't budge from the wall.

I've tried all my spells on this rune and the others, as well as different ways to pry it out, but nothing seems to be working.

How can I get these runes?