Not Rock

I have the weirdest lump stuff from my sister.
She was in town on the weekend and near this place that makes bullseyes and humbugs. I asked her the grab me a stick of rock.
I thought what came back was a giant green heart shaped lollipop, but it seems to be the end of what they make boiled lollies out of. One end it sort of stretched out about thumb thickness, but the other was probably a good 10cm across before it got pounded flat.
I think I’ll need to take a hammer to it to break bits off. Tasty, but strange.