Calathar's Chromatic Crystals

With an hours preparation the Arcanist is able to Evoke within two gemstones, power corresponding to their color. After spending the appropriate material components the gemstones shatter into fragments which float slightly above and behind the caster. These fragmented crystals perceive all threats within a 30 foot radius emanating from the Caster. So long as the Caster maintains concentration, the crystals will target any threats that enter this 30 foot radius with extreme prejudice, and will remain active for up to eight hours or until concentration is broken. Any creature or object that is hostile to the Caster which enters the radius of the spell, will be attacked, this attack is made using the Casters spell casting modifier. Upon a successful hit the attack deals 1d8 of the corresponding damage type for each crystal. Following the initial attack, the crystals share initiative with the caster and make one ranged spell attack of the corresponding damage type for each crystal, if there are no targets within the range of the crystals, they remain alert. At 4th level the spell creates two crystals. For every level past 4th level, create an additional crystal of which the damage type corresponds to the additional gemstone type you choose to use as a component when casting.