It sounds like a Velium weapon. They proc Velium Shards (12 point DD) at IIRC 30 or 35.
However it is a magic weapon and therefore you are now able to kill Willowisps. This is the sole aim of every sane Norrathian as the silly twinkling things just keep swarming all over the place.
You can also make decent cash from them which is entirely secondary.
The frequency with which a weapon's special effect is activated depends on the weapon and upon the wielder's DEX. DEX not AGI is the one for procs.
Your stats can only be improved by obtaining equipment that has stat boosting effects or by temporary "buffs", spells cast by or on you to modify stats. No trainer can improve your stats. Although much later on you can also use AA points to do this as well.
____________________________
Wherever I go - there I am.