Stoneskin

Version 0.17: This article may not be up to date for the latest stable release of Crawl.

Stoneskin
Level	2
School1	Earth
School2	Transmutation
Source(s)	Book of Geomancy Book of Transfigurations
Casting noise	2
Spell noise	0

Hardens the caster's skin. It has no effect on the undead or those under the effects of most types of transformation.

Stoneskin is a level 2 Earth Magic/Transmutations spell which temporarily makes the caster's skin hard as stone. This grants you a modest temporary bonus to AC:

AC Bonus: 2 + (spell power/20)
Max: +7

This AC bonus stacks with the bonus given by Statue Form.

Each casting increases the spell's duration by 8+2d(spell power) turns, up to a maximum of 50.

This spell functions much like Ozocubu's Armour, but has a less dramatic effect (roughly half the AC bonus without any of Ozocubu's dispel conditions, making it much more useful against enemies capable of inflicting fire damage). Stoneskin cannot be cast while under the effect of Ozocubu's Armour or most Transmutations spells; the only ones that do stack with it are Beastly Appendage, Blade Hands, and Statue Form. Ghouls, mummies, and vampires at less than full satiation cannot cast it at all.

Do note that Stoneskin will not notify you when its duration is almost over. Should you be in the middle of a pitched battle, consider casting it again when you have a spare turn to guarantee you maintain your AC bonus until the end of the fight.

History

Prior to 0.17, the effects of this spell were boosted while in Statue Form, using the formula 3 + ((11 * spell power)/100) (Max +14).

Prior to 0.15, this spell's AC bonus was dependent on your Earth Magic skill, not your spell power, using the following formula:

AC Bonus: 2 + (Earth Magic/5)
Max: +7 at 25 Earth Magic
w/ Statue Form: 3 + ((9 * Earth Magic)/20)
Max: +12 at 27 Earth Magic