More tourmaline everywhere. Roche Rock is known for this small monastery, built in ~12 century by a disgruntled monk who fled the domain of the Black Prince of Cornwall (reputedly benevolent and well liked by his subjects). Roche Rock, and the monastery, are composed entirely of granoblastic quartz-tourmaline rock containing little else (minor topaz and apatite). The quartz-tourmaline rocks such as this lack any obvious fracture permeability, and their origin remains enigmatic.