Ametrine, also known as trystine is a variety of quartz. It is a mixture of amethyst and citrine with zones of purple and yellow or orange. The colour difference is due to differing oxidation states of iron within the crystal which is caused by a temperature gradient during its formation.
As a healing stone, many believe it to have the powers of both amethyst and citrine, making it both a good money stone and to aid spiritual enlightenment. It is said to bring inner peace and tranquility.