Tourmaline is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. It's one of the most colorful minerals to be found. Trace amounts of chromium iron, and possibly titanium, create green and blue colors. Manganese creates reds and pinks, and possibly yellows. Some pink and yellow Tourmalines might owe their hues to color centers caused by radiation, which can be natural or laboratory-induced.
 
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* Photos show all sides.
* Sizes, shapes and colors my vary due to being a natural stone, being hand-carved and/or difference in computer monitors.