[5][6] It is translucent and the typical coloring is either blue, black, brown, or gray.

[4] The hexagonal crystal structure of osumilite is an unusual molecular make-up.

It can be found in high-grade metamorphic rocks, xenoliths and in the groundmass of rhyolite and dacite.

[3] Osumilite is found in the Obsidian Cliffs, Oregon; Sardinia, Italy; Kagoshima and Yamanashi Prefecture, Japan; and the Eifel district in Germany.

[3] Osumilite pseudomorphs are known from a number of ultrahigh-temperature rocks, including those of southern Madagascar.