Ametrine, also known as trystine or by its trade name as bolivianite, is a naturally occurring variety of quartz. It is a mixture of amethyst and citrine with zones of purple and yellow or orange. Almost all commercially available ametrine is mined in Bolivia.
Deposits often form with parallel bands of purple and golden quartz, sometimes with a band of clear quartz in-between. The combination makes it an interesting crystal metaphysically, connecting the solar plexus with the higher chakras, connecting physical and mental planes.