Price for Large Mithral Breastplate

[Patlin]

Armor for Unusual Creatures
The cost of armor for nonhumanoid creatures, as well as for creatures who are neither Small nor Medium, varies. The cost of the masterwork quality and any magical enhancement remains the same.

I'm trying to price a +5 Large Mithral Breastplate with the "Called" enchantment.

The easy part is:
Called: +2,000 gp (Magic Item Compendium p. 9)
+5: 25,000 gp

a medium mithral breastplate would be 4,200 gp.

Should I add 25% of 4200, or 50%, or more in order to have it fit a character polymorphe into stone giant form?

I'm the DM, so I could just pick a number, but I'm trying to be as by the book as possible. "Varies" isn't a heck of a lot of guidance from the SRD.

 

[Thurbane]

The SRD lists the cost for a large humanoid as 2x.

For the purpose of armor, I would consider a giant to be "humanoid" (i.e. two arms, two legs, roughly human bodily proportions)...

 

[Patlin]

The SRD lists the cost for a large humanoid as 2x.

For the purpose of armor, I would consider a giant to be "humanoid" (i.e. two arms, two legs, roughly human bodily proportions)...

Cool, I must have been looking in the wrong place!

35,400 gp would seem to be the answer, then.

 

[blargney the second]

So the mithral price gets doubled as well as the normal armor price? That makes sense, considering there's more material to use. So 4200 doubles to 8400.

On a related note, would a (non-mithral) large masterwork breastplate double from 350 to 700, or would the base price of 200 be doubled to 400 before adding the MW price of 150?

 

[Thurbane]

So the mithral price gets doubled as well as the normal armor price? That makes sense, considering there's more material to use. So 4200 doubles to 8400.

On a related note, would a (non-mithral) large masterwork breastplate double from 350 to 700, or would the base price of 200 be doubled to 400 before adding the MW price of 150?

That particular point has always been a bone of contention - I've seen it discussed here many times. Same with the cost for enchanting cold iron weapons. I don't think I've seen a decisive RAW interpretation either way.

 

[Elethiomel]

In addition, Mithral "includes" masterwork, so if doubling happens before masterwork addition and the Mithral price also needs to be doubled (even though it isn't the base price) you have to subtract 150 before doubling and then add it in again (or just double and subtract 150 afterwards, which is simpler and gives the same result).

 

[mvincent]

So the mithral price gets doubled as well as the normal armor price?

Yes. Although you can technically adjust for masterwork costs (but I don't recommend it, as even the Sage had trouble with the math when trying to do so).

From the FAQ:
"On page 217 of the Dungeon Master’s Guide, it states
that “the cost of the masterwork quality and any magical
enhancement remains the same” regardless of a creature’s
unusual size or shape. Adamantine and mithral both state
that items made from such material are masterwork quality
and the masterwork cost is part of the material cost listed.
How much would a set of mithral chainmail barding for my
warhorse cost?
A strict reading of the rules indicates that in such a case the
masterwork cost for armor should be subtracted from the
special material price before applying the multiplier for any
unusual size or shape of the intended wearer.
For example, according to the Armor for Unusual Creatures
chart on page 123 of the Player’s Handbook, a set of chainmail
barding for a warhorse (a Large nonhumanoid creature) would
normally cost 600 gp (four times the normal cost of 150 gp). A
set of mithral chainmail barding would cost 16,000 gp: 600 gp
for the chainmail barding plus 15,400 gp (the cost of mithral
medium armor [4,000 gp], minus the masterwork cost for
armor [150 gp], times 4)."

 

[Thurbane]

The Sage's advice is notoriously wonky, however.

I'd be inclined to add the +4000 after size modifiers, the same way and adamantine greatsword and dagger only have a small cost variance. That is just a gut feeling, and not neccessarily RAW.

 

[mvincent]

I'd be inclined to add the +4000 after size modifiers, the same way and adamantine greatsword and dagger only have a small cost variance. That is just a gut feeling, and not neccessarily RAW.

Well, it's been discussed at length before. Most of the special materials already have increasing prices by size/weight in some manner. Plus, I don't want PC's buying colossal adamantine fullplate cheaply and trying to make fortresses out of it.

But really it's not for balance sake... I just want some verisimilitude.

 

[Thurbane]

I can see your point.

Under RAW, I can purchase an adamantine greatsword, smelt it down and have it re-forged into 7 or 8 daggers, and make a massive profit.

Just as there is rules precedence for special materials costing more for larger items, there is also precedence for there being no significant increase. I guess it depends what the DM is comfortable with.