From PyroGuide
Emerald green stars. Silver tail is the result of the Black powder and Aluminium prime which has not completely burned off, and is not a feature of this star composition.
These stars generally give better and more brilliant colours than compositions without magnesium, Magnalium or Aluminium. This is because in the latter case the flame temperature is lower and the emitting molecules are not stimulated equally well.
Care must be taken to adequately protect the metals, if necessary, and to ensure good ignition as they are often harder to ignite. The stars show a higher burning rate than organically fueled ones.
Note that with some comps water must not be used for consolidation for there would be reactions with magnesium (with heat and hydrogen gas generation) in such a case. With Stars containing Chlorates and Aluminium, the use of Potassium nitrate in priming them may lead to ignition and is not to be recommended.