However, it is very much a mineral, for it easily fits the definition.
Ice definitely fits all of the parts of the definition of a mineral.
Water and water vapor are liquid and gaseous forms respectively. Since they are not solid, they don't fit all of the points of the definition of a mineral. Thus, they ARE NOT minerals. Ice may not be sold as mineral specimens, but it does have very important uses. However, in addition to its uses, it can be dangerous too.