Emily Dickinson Lexicon

DI'AL-LAGE, n. [Gr. διαλλαγη, difference, alluding to the difference of luster between its natural joints.]

A mineral, the smaragdite of Saussure, of a lamellar or foliated structure. Its subspecies are green diallage, metalloidal diallage, and bronzite. – Cleaveland. The metalioidal subspecies is called schillerstein, or shiller spar.