The vein tourmaline, based upon
the association of specific carbonate minerals, is further grouped as (i) albite-tourmaline-ankerite-quartz
veins (vein-1 tourmaline) and (ii) albite-tourmaline-calcite-quartz veins (vein-2 tourmaline). Both the
AMB tourmaline and the vein tourmalines (vein-1 and vein-2) belong to the alkali group and are classified
under schorl-dravite series.