Genesis

Genesis was an extremely powerful spell that created demiplanes.

Effects
The spell had to be cast in the ethereal plane. It immediately created a radius demiplane, which grew in radius to  over the course of about half a year, adding its initial radius every day. Repeated castings allowed the demiplane to continue growing by about of radius per casting, at the same rate as its initial creation.

The spell only created barren, lifeless demiplanes; life had to be added by other means. All that was created was land, atmosphere, water, and temperature.

Components
The spell called for verbal and somatic components, but also needed a significant fraction of the caster's lifeforce. The material component was a crystalline sphere.