ToME: the Tales of Maj'Eyal

Armour (from the wiki):
Armour reduces damage from every incoming melee and ranged weapon attack, even if it is not physical damage. It does not work on physical attacks that are not weapon based, such as Skullcracker. It does not work on damage from sources that are not weapon-based, such as spells, mental attacks, or breath weapons.

Stone Fortress:
When you use your Resilience of the Dwarves racial power your skin becomes so tough that it even absorbs damage from non-physical attacks.
Non-physical damage is reduced by 60–100cTL:200% of your total armour value (ignoring hardiness).

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Armour already absorbs damage from non-physical attacks. Nice skill lol

It actually does something - stuff on the wiki is just poorly worded here.
Basically, armor applies to any weapon attack, no matter the damage type of that attack.
Stone Fortress actually does do what it says - it just gives you X flat damage reduction against all non-physical damage while Resilience of the Dwarves is active.

True, but this to me reads "get value of armour and apply it after dam calcs". Is this when armour is usually applied?

name = "Stone Fortress",
type = {"wild-gift/earthen-power", 2},
require = gifts_req2,
points = 5,
mode = "passive",
getPercent = function(self, t) return self:combatTalentScale(t, 60, 100, "log") end,
ReduceDamage = function(self, t, dam, src) -- unused: called by default projector in data.damage_types.lua
local effArmor = self:combatArmor()*t.getPercent(self, t)/100
if not (src.turn_procs and src.turn_procs.weapon_type) and src.combatAPR then effArmor = effArmor - src:combatAPR() end
return math.max(0, dam - effArmor)
end,

The truly weird thing here is that that part of code is never called.
The part where Stone Fortress actually does something is in the Resilience of the Dwarves buff.