Hercynite - FeAl₂O₄

Habit: Dark blue-green, yellow, brown. Massive, as rounded black grains Translucent, vitreous Luster.

Environment: In high-grade metamorphosed ferruginous argillaceous sediments and in some mafic and ultramafic igneous rocks. Also in placers

Etymology: Named for the Latin name for the Bohemian forest Silva Hercynia, where the mineral was first found.