Nosean, also known as noselite, is a mineral of the feldspathoid 6Si O4). H2O. It forms isometric crystals of variable color: white, grey, blue, green, to brown. It has a Mohs hardness of 5.5 to 6 and a specific gravity. It is found in low-silica igneous rocks. There is a solid solution between nosean and hauyne , which contains calcium.
It was first described in 1815 from the Rhineland in Germany K. W. Nose (1753–1835). The mineral is rare but widespread, found in such diverse localities as ocean islands (e.g., Tahiti) and the La Sal Range.