Attune Gem Cost?

[RedDragons]

I was looking over the magic of faerun, and found what looked like a decent and relativity cheap lil bit of magic.

Attuning a Gem is what I can tell 50 gp per spell level + 1/25 xp of cost of creation + 50% in raw materials of what you use for the spell levels calculation.

Am I reading it right that it is cheaper then brewing a potion?



On top of the nifty little things that you can set them to be 5 ft radius detectors to set off traps if someone comes by, or even a certain sub type of creature ((like evil outsider)) , you can have it set off a spell like protection from evil.

[TuggyNE]

Attuning a Gem is what I can tell 50 gp per spell level + 1/25 xp of cost of creation + 50% in raw materials of what you use for the spell levels calculation.

Am I reading it right that it is cheaper then brewing a potion?

To start with, "cheaper than a potion" is not a very high bar; potions are pretty pricey. But here's a comparison table, assuming your reading is accurate:
{table=head]Level|Potion|Gem
0|12.5gp+0(?)xp|25gp+1xp
1|25gp+1xp|50gp+2xp
2|150gp+6xp|100gp+4xp
3|375gp+15xp|150gp+6xp[/table]

Which indicates it's better for 2nd and 3rd level spells, but not for 0th and 1st.

However, I suspect you've missed a caster level term in the equation, because that doesn't sound right. If so, then it's likely simply more expensive all around because of the perceived advantages. (Or perhaps it's the same price, and you're misreading base price as cost to create.)

[rot42]

It is phrased a bit funny, but I read it as requiring an expensive material component (the gem to be attuned) worth 50 gp per spell level, then you add to that the magic item price of 50 x spell level x caster level and XP equal to 1/25 of the second number. It is unfortunate design to have two "50 x spell level" terms, but the first one is the material cost and the second is the enchantment cost - this works the same as enchanting a mithral breastplate costs the same in XP and gold as enchanting a steel breastplate even though the first item costs significantly more in the marketplace. "Conveniently", the second 50 is halved when calculating cost to create, but the first 50 is just a material cost that you pay. I think the confusion might be coming with the term "base price", which has a particular meaning (http://www.d20srd.org/srd/magicItems/creatingMagicItems.htm) which is not the price of the basic unenchanted gem.

gold cost to create: 50 * (spell level) + (1/2) * 50 * (spell level) * (caster level) = 50 * (spell level) * (1 + CL/2)
gold cost to buy: 50 * (spell level) + 50 * (spell level) * (caster level) = 50 * (spell level) * (1 + CL)
XP cost to create: (1/25) * 50 * (spell level) * (caster level)

So, worthwhile if you really need the triggering effect and great for placing in treasure, but not great for general use.

[RedDragons]

Can you do a example of a level 1 caster using a level 1 spell , just so I know how your math is working .

[Gavinfoxx]

These things are great, because you can trigger them by touching. Just like the Runes, for divine spells, work great too. MUCH more generally useful than potions, much wider variety of things you can put on them, easier to activate when you need to, etc. etc.

[rot42]

Can you do a example of a level 1 caster using a level 1 spell , just so I know how your math is working .

Sure thing.

gem cost: 50 * 1 = 50 gp
base price: 50 * 1 * 1 = 50 gp
gold cost to enchant: (1/2) * 50 * 1 * 1 = 25 gp
XP cost to enchant: (1/25) * 50 * 1 * 1 = 2 XP

If you want to buy one on the open market, it will cost 100 gp. If you want to create one, 75 gp and 2 XP. Since choosing the number one as a random number often obscures the inner workings of a math example, here is a second level spell with caster level three:

gem cost: 50 * 2 = 100 gp
base price: 50 * 2 * 3 = 300 gp
gold cost to enchant: (1/2) * 50 * 2 * 3 = 150 gp
XP cost to enchant: (1/25) * 50 * 2 * 3 = 12 XP

This gem can be purchased for 400 gp or crafted for 250 gp and 12 XP.

[Crake]

basically what rot42 is saying is that it costs the same as a potion but with the additional cost of the gem itself which needs to be worth 50gp*spell level