Schiller \Schil"ler\, n. [G., play of colors.]

(Min.) The peculiar bronzelike luster observed in certain minerals, as hypersthene, schiller spar, etc. It is due to the presence of minute inclusions in parallel position, and is sometimes of secondary origin.

Schiller spar (Min.), an altered variety of enstatite, exhibiting, in certain positions, a bronzelike luster.

Source: Webster's Revised Unabridged Dictionary (1913)