Rapakivi

Rapakivi granite is a hornblende-biotite granite containing large rounded crystals of orthoclase mantled with oligoclase. The name has come to be used most frequently as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. Rapakivi is Finnish for "crumbly rock", because the different heat expansion coefficients of the component minerals make exposed rapakivi crumbly

Ours is the red one, Pyterlite.
It's common here but rare elsewhere.

“Very little grows on jagged rock. Be ground. Be crumbled, so wildflowers will come up where you are.”― Rumi