Tourmaline is a mineral within the silicate group. It is a complex mineral because the tourmaline group contains many different types. Each member has its own chemical formula which makes the general chemical formula of tourmaline the most complicated in the entire mineral kingdom: (Na, Ca)(Li, Mg, Al)3(Al, Fe, Mn)6(BO3)3(Si6O18)(OH)4. This mineral can be identified by; color (most commonly black and ranging from brown, violet, green, pink or in dual color pink and green); crystal(xl) description (parallel and elongated; needle-like, including radiating); Mohs hardness scale (7-7.5); cleavage (indistinct); fracture (uneven); luster (vitreous); streak (white). Of the three basic types of rocks, Tourmaline occurs in igneous and metamorphic. This basically means that this mineral is formed by heat or extreme pressure (which in turn produces heat). However, this mineral is resilient and can be found in the sedimentary rock, sandstone. The tourmaline crystal(xl) is asymmetrical at its axial ends (called hemimorphic). Hemimorphic xls are piezoelectric and often pyroelectric, meaning it has electrical properties. In legend, the tourmaline gem was also highly valued by alchemists who, perhaps because of it’s pyroelectric effect, believed it to be related to the philosopher’s stone. This was said to be the substance that would grant enlightenment, give power over spiritual affairs, reconcile opposites and change base metals to gold.
