Rock ID of find in Ramapo Mountains New Jersey

[crumpybumpy]

Any ideas on the ID of this rock found in the Ramapo Mountains of northern New Jersey? Thank you!

 

Amazon Forum Fav 👍

Diving for Pleasure and Treasure - Grab it through Amazon!

[IAMZIM]

It looks to me like a type of metamorphic rock. Maybe someone with better knowledge than I will chime in.

 

[Eu_citzen]

Hornfels? Or a "halleflinta"? (yeah, I don't know the english name)
https://www.britannica.com/science/halleflinta