oLulu's Magicka necromancer rotation for Stonethorn:
Not much to say about the rotation other than it is completely dynamic, keeping up Blastbones (BB) every 3rd Global Cooldown.
If you want something more static, this will work:
Boneyard is casted on the third skill so it’s empowered by the corpse created from the Blastbones exploding.
This also makes the rotation 10 seconds which is easier to manage.
Don’t be afraid to slightly overcast Siphon either because when you have stagger from a Dragonknight tank it actually does a lot of DPS - but best to play everything outside of this dynamically.