So I decided to do through and check this out frame by frame. Let’s see what’s going on here.

It looks like she’s reaching for her gem. But wait.

That’s not her gem. That’s beside her face. Her hair?! This pose is held for 2 frames.

Then she pulls it away and it passes by her gem in the movement.

And there it is, she has her bomb.

I’d also like to point out her gem isn’t glowing at all during this sequence, nor does the bomb form as light or anything like that.

Her gem’s the same colour here, the first frame in this shot.

Conclusion: Peri didn’t summon the bomb from her gem. She pulled it out of her hair. I love how she just stored that there in case she needed it.