Basically Size,Color and Amount of particles. That one has a cool color but it's pretty small and with a small amount of particles. Usually fatter is the flame more valuable it is,but depends,you need to keep many aspects in your mind.
The format it's important too,unique flames usually are payed better and yeah if a flame has a nice id,like 2 or 3 (first flames made) it's even more precious for collectors.
Flames made by epic forgers are valuable too,such as Fnugget or Gman80.
Last edited by Hisoka; Jan 7, 2015 at 02:10 AM.