Ken
Artisan
Note that the spells stored in the item must be of the same aspect as the Spell Store itself. Thus you cannot store Earth Battle Magic spells in a Celestial Spell Store item or vice versa.
Some spells are Earth and Celestial. If cast from memory, there's nothing in the call to indicate aspect compatibility to the recipient. Does it matter what school the spell slot was if the spell exists in both schools? Do the caster and the recipient need to briefly check OOG that their aspects did, in fact, line up? If the spell being stored is coming out of a scroll or potion, does that make any difference?