Tourmaline is a natural gemstone that come is a wide variety of colors. Tourmaline has a long history of use in jewelry, and was even instrumental in the 19th century when chemists were experimenting with the polarization of light. Tourmaline’s colors have many different causes. It’s generally agreed that traces of iron, and possibly titanium, induce green and blue colors. Manganese produces reds and pinks, and possibly yellows. Tourmaline forms in Pegmatites, hollow pockets