Stone of Spell Shaping (unstable)

This gem of spell shaping has the potential to be morphed into spell effects, and holds concentration on any such effects that are applied to it. The gem may be shaped into one spell, though the process of doing so has the potential to lash out against the caster with magical energy. Putting a spell into the gem requires the caster to role a wild magic effect. To end a spell held by the stone, the caster must cast dispel magic into the stone. The spell cannot be cast with a spell of a level higher than 5th.   The caster gets the feeling that the stone has more potential to it, but that any such potential is beyond their reach at the moment, as attempts to understand the stone's potency or cast higher level spells into it are meet with unexpected magical effects.   The Stone of Spell Shaping requires attunment.