Alexandrite was names after the Russian Czar Alexander II because it was discovered on his birthday.  It is known for it's ability to appear different colors in different types of light.  In incandescent light, it is red or purple, but changes to green or blue-green in natural sunlight and most types of florescent light.  It is said to be a stone of joy and wisdom and is associated with the elements of wind and water and the heart and head chakras.  Alexandrite is an aid to spiritual growth and transformation.  It helps to get the heart, third eye and crown chakras to work together.  It helps to bring joy in spiritual rather than material things.  It is said to strengthen intuition in critical situations. Some Metaphysicians say it can help us return to the beginning of time and connect with our spiritual origin,   It is the birthstone of June but it's rarity, at least in gemstone quality, makes it very expensive. 
     For physical ailments, Alexandrite is said to help recovery from surgery and long-term illnesses.  It does this by restoring and balancing internal energies.  It has also been said to strengthen blood vessels.