Detail: Green Tourmaline is a complex sodium lithium boro-aluminium silicate hydroxide in the Tourmaline group found in granites and granitic pegmatites. Green Tourmaline, known as Verdelite.
Chemical Composition: Na(Li1.5,Al1.5)Al6S6O18(BO3)3(OH)4 - NaFe3(Al,Fe)6Si6O18(BO3)3(OH)4