Hercynite
Hercynite is a spinel mineral with the formula FeAl2O4.
It occurs in high-grade metamorphosed iron rich argillaceous sediments as well as in mafic and ultramafic igneous rocks. Due to its hardness it also is found in placers.
It was first described in 1847 and its name originates from the Latin name for the Harz, Silva Hercynia, where the species was first found.