Tourmaline (Elbaite)
Na(Li,Al)3Al6[(OH)4I
(BO3)3I
Si6O18]
ditrigonal - pyramidal, 3m
polished plate perpendicular
to the c-axis of a multicolored zoned crystal.
Anjanabonoina, Madagascar.
Long diameter:13,5 cm, weight
188,5 g. Inv.No. 90/14.
Tourmaline
principle sketch of a zoned
crystal perpendicular to the c-axis.