Q: What is tourmaline, and what colors does it come in?

 A: "Tourmaline" refers to a large group of minerals with similar crystal structure and varying chemical composition. Very few naturally occurring tourmalines are suitable for use as gemstones. Tourmaline is a relatively hard (7.0 Mohs' hardness) gemstone, consisting of borosilicates of aluminum, sodium and magnesium . Tourmaline is one of the most diversely colored of all gems and  minerals - occurring in nearly every color imaginable.
In Maine, the most commonly occurring colors are shades of green, blue green,  and pink.

 Q: Is tourmaline rare? How valuable is tourmaline?

 A: It is uncommon to find tourmaline possessing a bright attractive color (pink, red, green, blue) suitable for gemstones, which is also  free of defects and inclusions. Such specimens yield quite valuable finished cut stones. As a mineral, tourmaline is found throughout the world,  most often as a black variety called schorl, which has no value as a gemstone.

 Q: I've heard of Watermelon Tourmaline. What's that?

 A: "Watermelon Tourmaline" is a term used to describe the unique tourmaline crystals found in Newry , Maine by the Plumbago Mining Corp. These crystals had the curious property of having a green outer "skin" and a deep, reddish pink "core"  - hence the term "Watermelon"  [Photo].

 Q: So tourmaline can have more than one color in the same crystal? How is that possible?

 A: Tourmaline is unique as a gemstone, not only in that it occurs in nearly every possible color, but also because a single crystal may exhibit as many as three or four different colors.  The cause of this odd behavior is a combination of subtle changes in chemical composition and crystal structure , which occurred when the tourmaline crystal was formed. As a result, some  tourmalines may  be cut so that they are, for example, green at one end and pink at the other!  [Photo]

 Q: How is Maine Tourmaline special?

 A: For nearly 200 years, Maine has produced some of the finest tourmalines in the world. Maine is especially noted for its many shades of premium quality pink and green tourmaline.
Tourmaline was the first gemstone to be mined in North America.

Mining and Quarrying - Frequently Asked Questions = Maine Goverment

Tourmaline: Maine's State Mineral

An Introduction to Mineral Collecting in Maine