Hmm, I'm thinking the coppery smell might make more sense as its "angry smell" since it'd resemble blood.
How about:
Tourmaline dragons usually have no particular odor but can produce strong scents when excited - when pleased by flattery it may produce a salty fragrance comparable to a chrysanthemum-perfumed sea breeze, while an angry tourmaline dragon produces a sharp coppery reek that resembles blood.