You don't so much cast a Miracle as request one. You state what you would like to have happen and request that your deity (or the power you pray to for spells) intercede.

A Miracle can do any of the following things.

Alternatively, a Cleric can make a very powerful request. Casting such a Miracle costs the Cleric 25,000 gp in powdered diamond because of the powerful divine energies involved. Examples of especially powerful miracles of this sort could include the following:

In any event, a request that is out of line with the deity's (or alignment's) nature is refused.

A duplicated spell allows Saving Throws and spell Resistance as normal, but the save DCs are as for a 9th-level spell. When a Miracle spell duplicates a spell with a material component that costs more than 100 gp, you must provide that component.