Gargoyle Heart of Stone

Level 6.

Gargoyles must often face stinging hails of arrows and sharp, piercing blades in their battles against the Tzimisce viovodes and their armies. This ritual was devised by the Tremere to protect their strongest and most valuable Gargoyle servants and warriors, and makes them devastating opponents on the battlefield. the skin of the Gargoyle takes on a decidedly more rocklike appearance after this ritual.
System: Effective only on Gargoyles of the seventh generation or lower, this ritual must be enacted on seven successive nights. On each night the Tremere must expend one Blood Point, which is mixed with mortar and mercury and then ingested by the Gargoyle. Each night, the Tremere must roll Stamina + Occult (difficulty 6), although a point of Willpower may be spent to gain an automatic success. If the ritual succeeds on all seven nights, the Gargoyle's internal organs (or what remain of them) become hard as stone. Any piercing weapons used against the Gargoyle have their Dice Pools halved, and it is impossible to even attempt to stake the Gargoyle without a combined Strength + Potence of 7 or better. This ritual lasts until the next summer solstice, but the Tremere may, at the end of the ritual, exert extreme concentration and expend a permanent point of Willpower to make the ritual permanent.

(This is one of the pre-Visceretika Gargoyle rituals)