What are the rules for making Custom (Epic) Spells?

[Sims]

I don't have the book for it, and I know I have a few pretty godly spell ideas. What would the DC's be to make a spell that turned enemies into a pile of gold/platnium?

[HiddenLineage]

No clue, but you got me thinking about something. Polymorph Other Object. I know it says you can't make money, but what if you Polymorph something into a Dragon's Eye then use a Permanency spell on it and sell it?

[TheCoelacanth]

Here's an epic spell that should do it.

Transform seed (DC 21, +10 creature transformed to inanimate substance, +5 hardness (I assumed the same hardness as iron, gold is probably lower but I couldn't find it)), +20 1 action casting time

Cost to develop: 11 days, 504,000 gp, 20,160 XP

Transmutation
Spellcraft DC: 56
Components: V, S
Casting Time: 1 standard action
Range: 300 ft.
Target: One creature
Duration: Permanent
Saving Throw: Fortitude negates (DC 20 + casting attribute modifier)
Spell Resistance: Yes