Correct spelling for the English word "armenium" is [ɑːmˈiːni͡əm], [ɑːmˈiːniəm], [ɑː_m_ˈiː_n_iə_m] (IPA phonetic alphabet).
A pigment of the ancients, produced by grinding the Armenian stone, a supposed blue carbonate of copper combined with lime.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.