Description: Tourmaline - October Birth Stone With Chemical Formula Tourmaline is a group of complex borosilicate minerals with the general formula XY₃Z₆(T₆O₁₈)(BO₃)₃V₃W, where: X = Ca, Na, K, or vacancy Y = Li, Mg, Fe²⁺, Fe³⁺, Mn²⁺, Al, Cr³⁺, V³⁺ Z = Mg, Al, Fe³⁺, V³⁺, Cr³⁺ T = Si (mostly), with minor Al or B V = OH, O W = OH, F, O A common simplified formula covering the main species (elbaite, schorl, dravite) is (Na,Ca)(Mg,Li,Al,Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄.
Description: Tourmaline - October Birth Stone With Chemical Formula Tourmaline is a group of complex borosilicate minerals with the general formula XY₃Z₆(T₆O₁₈)(BO₃)₃V₃W, where: X = Ca, Na, K, or vacancy Y = Li, Mg, Fe²⁺, Fe³⁺, Mn²⁺, Al, Cr³⁺, V³⁺ Z = Mg, Al, Fe³⁺, V³⁺, Cr³⁺ T = Si (mostly), with minor Al or B V = OH, O W = OH, F, O A common simplified formula covering the main species (elbaite, schorl, dravite) is (Na,Ca)(Mg,Li,Al,Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄.
