(1) Complex composition: Tourmaline is an extremely complex boro-aluminosilicate mineral, and it is the gem mineral with the most complex chemical composition in nature. It may contain one or several elements such as magnesium, σίδερο, λίθιο, potassium, νάτριο, και τα λοιπά. Due to the different content ratios of these elements, tourmaline often has different colors. Οπως [...]
