Ilmenite is a gray or black, weakly magnetic mineral found in basic igneous rocks, notably basalt, and metamorphic rocks. It is nearly pure iron (II) titanium (IV) oxide (FeTiO₃) and occurs as tabular to fine, scaly crystals in the rhombohedral system, and as compact masses or granules. Ilmenite has a metallic luster; hardness 5–6, relative density 4.7. About 90% of the world's annual production of titanium comes from it, major deposits being in Russia, Norway, Quebec, and Wyoming. The discovery of ilmenite on the Moon has opened up the possibility of mining this mineral to supply both building material and oxygen to a lunar base.