Of the tourmaline family, green tourmaline is the most commonly seen...in a very broad variety of greens. However, it also occurs in other colors. The most frequently seen alternate color is pink, the most intensely hot pink version being specifically referred to as rubellite. The blue variety bears the name indicolite. There are other varieties with a deep, bright turquoise or teal color, which have acquired the very general association with the name Paraíba, evidently the first major occurrence of this version of tourmaline.The Paraiba nomenclature is currently inaccurate, since the Paraiba mine produces no new tourmaline material, as I understand it.

Some other variations on tourmaline can be found in which two or more colors are brought together within the same tourmaline crystal. Depending on the manner in which it's cut, one of the notable results is a slice of such a crystal that's often referred to as watermelon tourmaline, due to the suggestion of the outer shell with one or more divisions of color occurring on the inside of the shell.

Examples of rings in which green tourmaline has been set:
http://artwork-inform.com/sring4.htm
http://artwork-inform.com/jlrgau20.htm
http://artwork-inform.com/jlrgau18.htm
http://artwork-inform.com/jlrgau23.htm
http://artwork-inform.com/jlpnd02.htm
http://artwork-inform.com/pdtchtrm.htm
http://artwork-inform.com/pndtorm1.htm
http://artwork-inform.com/pintorm1.htm
http://artwork-inform.com/pndlapis2.htm