Garden of Glass
CrIg 20
R: Voice , D: Mom, T: Ind +2
This spell turns a portion of a desert the size of 100 large fire camps into a garden of glass by heating the sand to the point where it actually becomes Glass. This leaves the affected ground not only beautiful but dangerous to travel through. Animals will avoid the terrain but those that risk crossing it will suffer cuts from the cutting glass. Story tellers are encouraged to ask for a dexterity roll. the better the result the less damage (+0/+5/+10). A bad roll could represent the victim falling face straight into the garden. A painful event for sure.
//(Base 5,+2 Voice, +0 Momentary, +0 Ind,+2 size)//
{{WilliamEx.}}
Sounds MuTe to me, not CrIg, to be frank. At the very least it will require a Te prerequisite.
Do you require a Corpus requisite to burn flesh and an animal requisite to cook your meat medium rare?
When you heat enough sand, it becomes glass...
William
I would tend to agree. Although if the process is well understood, I could see it falling under Rego.
At first I thought it was an assassin's trick, turning someone's dessert into glass as they ate it to destroy their insides. Then I realized the size and sand indicated something else. 
Chris
Not necessarily. I've seen a lot of heated sand not become glass, whether under a hot sun or under a campfire.
Chris
Lol .. removed the extra "s" I still got some quirks with English despite my exposure XPs 
W
Yup, this could work with ReTe. This is like making ice. You can use PeIg to freeze water, or ReAq to change water from one state to the other.
There's usually more than one way to skin the proverbial cat. Sure, glassmaking is probably well enough understood that glass would be a natural state that sand could be in, so ReTe to change the state.
But I could also see CrIg working. Yes, as was pointed out, sand + fire does not always equal glass. But it can. Temperature of fire needs to be correct. Sounds like something that CrIg should be able to handle.
How thick and tough do you want the glass to be? Your mention of a person taking damage moving across it seems to suggest that it is formed into glass-razor blades or something. Is the damage supposed to be from thin glass breaking, and the shards cutting the person? Or is it thick glass that has sharp edges built in? I'd say the latter might need some requisites, but I'm not sure what.
I'd probably increase the base level, but that's about it.
And I should hurry and mention I have no experience with glass-making, so have no clue as to the required temperatures.
I also think the most appropriate combination would be ReTe -- and yes, the making of glass was fairly well understood since antiquity.
With Ignem, however, you need really high temperatures (1200C) unless the sand contains the "right" mixture of chemicals (in which case you can drop as low as 600C). Also, if you magically heat something, that something will in turn non-magically heat nearby stuff, and when the spell wears off, the non-magical heat will remain... with these levels of heat I think that the spell would have some side effects .
Correct. A common side effect 8and why POF is not so popular in cities) is that you can set things of fire by consuming someone in flames. nearby stuff like tatch roofs mitch catch as well 
Cheers,
Xavi
I was thinking of unrefined shards of glass with some bigger parts that could poncture. The end result would not be refined as like mentionned, there is no Rego requesite.
There seems to be some concerns with the base level. I don't have the book with me but I used the one where it heats till it glows white. Seemed enough. What are everyones taughts on this?
W
If your just blasting sand with heat I don't think your going to get shards. Personally I think you'd get something like Trinitite. Which was glass formed when the first nuclear bomb was tested. That might also gives you an idea of the magnitude of heat you'd really need to instantly turn unrefined sand into glass.
I've seen pictures taken at the Trinity sight before the Trinitite was bulldozed up and hauled away. Closer to the blast it was a kind of a foamy bumpy surface. Further away where the heat didn't penetrate as far into the ground you got little irregular balls of glass. The surface melted into glass but melted glass takes up less space then sand and it beaded up like water on a windshield as it cooled.
You probably need Base 15-25. Base 5 is stated as "glow red-hot", and even white-hot isn´t really enough.
Also do note that two of the base 5 and 10 guidelines should be switched, because red-hot is much hotter than "melt lead" is.
The spell will be hard pressed to create what you want, but you can get something roughly in that direction at least.
Of course, the lingering heat after the spell is used will make the affected area seriously offlimits for a while.
Ok this sounds good but at those base levels, it might be worth while to add a muto catalyst (requesite) and keep a lower base. What do you think?
W
I have to agree with the people saying that melting sand requires a lot of heat i.e. a higher base and what you'll get is blobs or crusts of glass rather than shards but the ground will be lethally hot for hours. ReTe is almost certainly the most efficient way of getting what you want. The only way I can think of to get the garden of glass effect long term without Re would be MuTe(Ig) to briefly turn an area of sand into flame which freezes into wavy glass daggers as the spell ends. If you want shards without using Te then Cr(Re)Ig could let you melt sand then move the heat into the centre of the glass so as to cause thermal shattering NB this needs to be at R: sight because yellow hot, ultra-sharp shrapnel will kill you dead.