Any geologists in the house?

I came across this cracked open boulder while ascending a brook in the Macintyre Range.
Any thoughts as to what sort of rock this is and what cooling history would result in it?

http://adkhighpeaks.com/neil/outdoor pursuits/avy-macs_2016/Avy-mac_0044.html

Maybe this? Not sure.

https://en.wikipedia.org/wiki/Labradorite

On MYCCR someone posted this link in response to my query there.

Could be a coincidence.

Labradorite has a distinct way it interacts with light; it looks like its referred to as labradorescence in these links. Moving it back and forth in the light, light enters and is reflected/refracted back giving a variety of colors. It's a pretty unique stone. I have a piece about the size of a baseball on my table, primarily green and blue. I'm no geologist, but it could be the same.

Did you notice any unique play with light?

The mineral is likely labradorite. The rock is likely anorthosite.

https://en.wikipedia.org/wiki/Anorthosite