The Investigator Antiquarian archetype gives up potions for Trinkets that "count as formulae". They then use these trinkets to cast spells as an arcane caster, but does not suffer from arcane spell failure.
When using extracts, standard alchemist/investigators don't require concentration checks, but do provoke AOO's.
From the flavor description, they almost sound like single use activation items, although I don't think that is what they are meant to be.
I would assume that like a standard alchemist/investigators the trinkets don't require concentration checks, but do provoke AOO's.
“However, instead of creating extracts, an antiquarian casts spells as though he were an arcane spellcaster, which means he can affect other creatures with his spells. An antiquarian does not suffer from arcane spell failure.”
I think it is in most ways arcane spellcasting, so things like casting time and concentration are there too.
The most telling part is that we are told it’s like arcane spellcasting, and then we are given an exception for how it is different.
Another question came up in our group regarding Pearl of Power/Boro Beads.
Most investigators would use Boro beads the same as alchemists, but because the Antiquarian "prepares spells by meditating and charging relics with supernatural power" I would think a Pearl of Power is a better fit.
Anyone want to point out the flaw in that thought process?
Once per day on command, a pearl of power enables the possessor to recall any one spell that she had prepared and then cast that day. The spell is then prepared again, just as if it had not been cast.
An antiquarian prepares spells by meditating and charging relics with supernatural power, which has the same requirements and limitations as preparing extracts.
So the antiquarian prepares spells. And the antiquarian casts spells. So the Pearl should work fine.
I don’t think the boro beads would work. The antiquarian prepares spells similarly to extracts, but they are still spells for most purposes.