During excavations some wizards came upon the workshop of the 5th dimensional being that created everything, essentially god. In that workshop were many notebooks chocked full of the techniques of creation (Turning 5th dimensional magic energy into 3 dimensional objects) Every once in a while godly existence gets boring and you need to spice things up, so some notebooks contained various ways of destroying things. Over a few hundred years our intrepid wizards translated one such way. It involves dropping something. Luckily wizards have access to airships with a ceiling of 5000m.
- It can be any currently known natural substance or substances in our world even if the wizards have no idea what it is. Natural is key. Avoid Man-made substances/chemicals.
- The least complex the better.
- No nuclear bombs, balls of pure gunpowder, or metal spheres filled with nitroglycerine. (See #1 on man-made)
- It must fall a minimum of 300meters and a maximum of 5000.
- Weight limit: Don't drop a mountain on the town.
- The wizards should be safe from the resulting destruction. (Most of the time. Some of the larger craters will have definitely destroyed the wizards who made it.)
- It must be scalable. The God-creator used it to make a 800km diameter crater. The wizards will use it to make craters between 100m and 15km.
- When the wizards are “creating” the object it will be stationary and inert. Once their spell is complete it will become “fully real” and any chemical reactions will begin.
- The wizards need to be within 30meters of the object while creating it. So when it is “fully realized” the object must not instantly kill them by its proximity.
- The object created is permanent and must not cause undue devastation to the world beyond its initial impact.
Notes:The object doesn’t necessarily need to be explosive, but I feel that’s the only way. I’ve done the math for the impact of a 100 ton pure iron sphere dropped from 5000m, but it doesn’t have nearly enough energy for what I’m looking for. I originally wanted the objects to be actual meteors falling from outer space or teleported into the atmosphere, but my magic system doesn’t really allow for that. There have been questions about medieval explosives, stone age explosive, and others, but I believe this question to be unique and not a duplicate due to the criteria.