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Fig. Par32 Photograph of a multicolored tourmaline from Brazil (Paraiba mine Source RC Gemmas). The tourmaline has been cut perpendicular to the c-axis (thin parallel plate, both sides polished). The sample is from the lot shown in Fig. Par29. The string of craters visible in the picture is induced by LA-ICP-MS analysis.Different color zones are visible.
Fig. Par33a Variation in Sb-, Mg-, Pb- and Be-concentrations The maximum of the Mg-concentrations is well correlated with the end of the “neon”-blue growth phase. The Mg-influx coincides with the first major increase in Mn and the trend of increasingly higher Mn/Cu-ratios with continuous growth after the “neon-blue” growth stadium (Fig. Par33a, and Par36b).
Sb-concentrations are particularly low in the center of the crystals (purple growth phase) and increase with the beginning of “neon-blue” growth phase.
Be-concentrations increase in this color zone as well as the Pb/Be ratios (See also Fig. Par36b).
Fig. Par33b Variation in Ca-, Fe-, Ti- and Zn-concentrations These elements are enriched in the green rim. Ca is depleeted in the core and enriched in the rim (compare wiht EMPA, Fig. Par28b)
Fig. Par34 Ternary Mg-Pb-Zn diagram (LA-ICP-MS analysis, in µg/g)
The chemical variations in the relative amount of Mg-, Pb- and Zn-concentrations can be correlated with growth zones in tourmalines. From the core to the rim the trend is marked by highly variable concentrations along the Pb-Zn boundary, with a short dominance of the Pb- relative to the Zn-concentrations in the “neon-blue” copper growth phase. Mg-concentrations are in generally low in comparison to the Zn- and Pb-concentrations. Note that the trend reverses from the core to the rim of the crystal (follow red arrow). In a first step the trend points towards the Pb-concentrations (high) and in a second step towards the Zn-concentrations (high).
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LA-ICP-MS Chemical Analysis Profiles of Paraiba Tourmaline, Batalha Mine
