Where is Archanite ore???Follow

I am a 365 miner currently working in outlands and I have never seen archanite?

Is this a rare spawn? If so of what?

as stated its a transmute. ive only found it in rich thorium veins. but i got 1 this weekend off a korium node in nagrand. my question is should i keep the crystal or do the transmute? i have 10 bars and i think about 15 crystals in an alt bank. iddie.