Tourmaline

Tourmaline is a group of minerals comprised of a complex boron-aluminum silicate with one or more of the following: magnesium, sodium, lithium, iron, potassium or other metals. It appears in light from dark red to purple as well as brownish variations of these hues - light to dark green, yellowish-green, greenish-yellow, brownish-orange. It also grows bi-coloured.

Varieties
Bi-coloured, watermelon, cat's eye, alexandrite-like (rare) .

Sources
Sri Lanka, Brazil, USA (California, Maine), Madagascar, Tanzania, Kenya, Russia, Afghanistan, Pakistan (prime new source).

History
Dutch children played with tourmaline because of its ability to attract light objects. The stones were called "aschentrekkers" (ash drawers).

Cuts & Uses
Any cut may be used. Some are carved, some fashioned into beads. Cat's eye are always cut en cabochon. Sometimes carved to make use of more than one colour.