One of my favorite gemstones that occurs naturally in nature! Most tourmaline deposits are created by molten magma flowing through rocks. The molten magma cools and creates veins in the rock that are rich in certain minerals. The veins can contain a solution of water and minerals such as iron, lithium or manganese.These are the elements that give tourmaline's their unique colors, ranging from red, green and blue to yellow and orange. As the watermelon tourmaline's crystal grows it contains different concentrations of certain elements such as manganese and lithium, which cause the gem to change color from a pink center to a green outside.