Chondrodite

Chondrodite is the troll god of love who causes trolls to fall in love by hitting them on the head with a rock. The name is a rock-related play on Aphrodite.

Geology

Chondrite is a mineral found only in meteoroid impacts. Chondrite leaves affected Trolls starstruck.
As found on Roundworld, it is a largely non-metallic asteroid material: a very old rock indeed.