Hornblende is a name used to describe a group of minerals which can only be distinguished through detailed chemical analysis. For this reason the minerals in the group are generally referred to simply as hornblende. They're important constituents in igneous and metamorphic rocks and mostly occur in dark colours such as black, dark green or brownish green.
Hornblende has no real use in industry and is mostly used as a mineral specimen.
Hornblende on Geology.com