pyrite?

These were landscaping rocks I found, so I'm not sure of their original origin point but I do know they're all from around the same place. The gold/yellow stuff has some rainbow glints to it, and the white crystal ish stuff is pinkish in real life. bottle cap for scale.

Given this by someone who found it among a collection. I'm assuming it's pyrite crystals but I've never seen them in layered formations like this. What else is it?