Appearing in hues of blue, yellow, pink, red, black, and green, Tourmaline’s variety of colors have made it a popular gem choice for necklaces, bracelets, and pendants.  It contains color crystals that are strongly dichroic—meaning that they are of different colors when viewed in the direction of different axes.  Tourmaline is the birthstone of Libra, and the recommended gift for the 8th wedding anniversary.