Kyanite is a blue silicate mineral.  It's name comes for the Greek word for blue.  It's hardness varies depending on the direction of the crystals within the stone.  Kyanite is used in making porcelain and insulators.  It is rarely used as a gem stone because of the difficulty of cutting it into attractive shapes, though, in recent years, it is being used some, but cut as cabochons.  It is said to aid in developing psychic and spiritual awareness.  It aids understanding and communication, with other species as well as with other people.  It is an aid in expressing creativity so is useful to artists, writers, poets, musicians, etc.  It is claimed that this stone cannot retain negative vibes of any kind so helps you stay positive.  It is said to benefit the throat chakra and organs in that area and in the upper chest where blue is the dominant light color.  It is also said to relieve pain and reduce blood pressure.