Mavin's create volcano

Mavin's create volcano was a 10th-level Arcanist spell created in the days of Netheril.

History
The spell was created by Mavin around -601 DR (3258 NY). This spell could no longer be cast due to the restrictions placed on magic by Mystra after the near cataclysmic destruction of The Weave by the casting of Karsus's avatar in -339 DR (3520 NY).

Uses
Casting Mavin's create volcano caused a minor earthquake to erupt in the desired area. After a week’s time, ash and smoke exploded from the earth and, within a month, the mountain site would erupt into a powerful volcano.

Drawbacks
The spell was never cast in Netheril‚ but every arcanist sought the knowledge to conjure a devastating volcano, and but they were stilted due to the terrifying effects the spell would have had on the ground-dwelling creatures, such as dwarves and elves.

Spell components
The components needed for this spell were a mantle of sewn diamonds which acted like a ring of fire resistance, a helm of brilliance, and a mythallar, which was placed at the location of the volcano.