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Fig. Par72a-b Color-zoned unheated copper-bearing tourmalines from Mozambique (GRS collection). Note the typical succession of colors from the core to the rim: Purple core, greenish-blue and blue intermediate growth zone and green rim. The outermost rim may be yellowish-green followed by a dark green outer layer. The same type of materials was also described in the literature (Lit. Par33). ED-XRF chemical analyses of the color zones are included. According to our classification (Fig. Par90a), the outer green rim in Fig. Par72a is a “Type C”-tourmaline.
Fig. Par73a-b Microphotograph of two Mozambique tourmalines with vivid green and vivid purple color. Both faceted stones contained growth tubes with orange colors. Purple “halos” were absent.
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Color-Zoning in Copper-Bearing Tourmalines from Mozambique
