I had a thought. This is the "it's a question" thing from the end of my last post in my game.
Here is how things appear to me at the present moment:
1: It is possible to destroy an object via magic, in a high-magic Verse.
2: It is normally not possible to destroy an object via magic in a low-magic Verse.
3: It is possible to sacrifice an object, and designate that it has been "consumed by the magic," even in a low-magic Verse (as I myself have done with several emeralds that I would not normally have been able to destroy).
What this leads me to conclude is:
A: It is possible to destroy an object (an errant iceberg, for instance) even in a low-magic Verse, simply by sacrificing it to power a spell that would normally be otherwise possible within said Verse.
After all, it wouldn't be fair if I could sacrifice that iceberg, and still have it there, to use as a wall against an enemy ship, for instance, right? It would have to be completely and utterly gone, destroyed beyond all use, wouldn't it?
Despite the handy example drawn from my current in-game predicament, I've actually been contemplating a spell like this from back when I sacrificed those emeralds. The idea I had originally was to 'sacrifice' part of a castle wall in order to bore a hole in it. Actually the spell idea that went with that was along the lines of "sacrifice it now and store the energy for later use" but I haven't really figured out how to word that spell yet (for instance, I sacrifice this iceberg, and icebergs are a fairly usual thing, so I would get a +4 for it (maybe +6 for it also being inconveniently large)... only I don't use that +4 right now, I save it in a sort of arcane battery and discharge it next time I need a +4 for something - maybe it decays to a +3 if I wait too long, or somebody jimmies my battery when I'm not looking).
Before you get too excited, remember that something has to be yours before you can "sacrifice" it in any meaningful way. I'm pretty sure that destroys most of the munchkiny ideas right off, but if you have any schemes left after taking that into account, I'm interested.
Edit: The idea of "storing" the bonus in an "arcane battery" would probably be simplest to model with a M1@4 Bonus Skill Check, designed such that successful casting of the bonus spell boosts a later magic skill check of your choosing.
Could you plant a flag on the iceberg and 'claim the land'? Lol.
Probably. But you would also have to involve the iceberg in your spell someone to use it as a material component, so I would suggest wearing a life jacket or similar flotation device.
hahah, unless the spell is to make a boat from the iceberg, or even, es to not leave it in the way of the other ship (in this case) in some ice-aircraft :P
I'd say 'You, the PC, have to destroy the iceberg. Here's an icepick. Get to work.'
I did try to write a fantasy novel with an iceberg ship. The notion of a nigh-indestructible, and absolutely huge battle platform is just kewl. I think their is some history on this.
Scott's points about having to possess and/or control the object sacrificed are major aspects of what I was thinking.
I would also observe that "destroying" the object does not necessarily mean that the thing disintegrates. It means that it is rendered useless for future use in casting a spell. Your emeralds might be crushed to dust, or reverted to coal, or liquified to drain away, or evaporated as carbon gas, or rapidly oxydized (burned). The sacrifice of the iceberg might mean that it melts, or it might mean that it is crushed into millions of ice cubes rapidly spreading out across the surface and naturally reconnecting into a sheet of ice surrounding the ship, or that it evaporates or disintegrates leaving a huge space in the ocean into which surrounding water is rapidly dragged creating a waterspout as it all collides in the middle--destroying an object that size is itself a very hazardous action, and doing so in an incidental and inherently uncontrolled way is the more so.
Eric's suggestion concerning the ice pick and your quite appropriate use of the word "sacrifice" also point up another aspect. If you sacrifice and animal (or, if appropriate to the situation, a human), you kill it. The body is not destroyed, of course; it's not necessary for the body to disintegrate for the creature to be sacrificed. If it is necessary for the body to disintegrate, then you put it on an altar and set it afire. It is not impossible for an object to be incidentally destroyed by the release of magic in the spell, but the suggestion that an object is destroyed in the casting is more about whether you are doing something with it that will render it useless for the repetition of the spell.
In view of that, the destruction of the iceberg as a material component could transmute it to a huge floating mass of vegetation--no longer an object that can be used for purposes of casting this spell, and of no particular use otherwise, but still an obstacle with which you would have to reckon.
Referees are supposed to be alert for efforts to end-run the rules by such tricks. If you're telling me that the emerald you use in the spell "is destroyed" I'll assume it shatters in the process as it hits the deck, having been rendered brittle by the magic. Tell me that an iceberg "is destroyed in the casting", I'll ask you how it is destroyed, and add that to the spell as an intended effect.
Oh, and part of a castle wall is not really a discrete object, so I would object to a casting that worked that way. If you want to include the entire wall, though, I would probably require you to "compass it about" somehow, such as walking the full length, possibly on both sides.
--M. J. Young