Clarification

[Ghostwidow]

For the gem of seeing, does it grant you the actual ability via monster ability, or does it cast the divination true seeing on you? Trying to figure out if non-detection can beat the gem since I know it beats the spell, but not the monster ability.

[Dork_Forge]

It gives you true sight, it doesn't involve the spell True Seeing at all.

[Ghostwidow]

Right, but since its an enchanted item, it wouldnt use the spell to do so?

[Dork_Forge]

The spell has nothing to do with truesight in general, it's just one way to get it and isn't even all the spell does.

Unless something mentions the spell specifically, truesight has nothing to do with trueseeing and enchanted items only use spells when they tell you so.

[Unoriginal]

The spell has nothing to do with truesight in general, it's just one way to get it and isn't even all the spell does.

Unless something mentions the spell specifically, truesight has nothing to do with trueseeing and enchanted items only use spells when they tell you so.

Indeed. The magic item text tells you everything, some items do cast spells, others don't.