galaxite

… (zinc aluminum oxide, ZnAl₂O₄), and galaxite (manganese aluminum oxide, MnAl₂O₄). The colour of magnesia spinel ranges from bloodred to blue, green, brown, and colourless; gahnite is dark blue-green; hercynite and galaxite are black. These minerals are found as glassy, hard octahedrons, grains or masses in basic igneous rocks, granite pegmatites,…