Mn-rich tourmaline from Austria: structure, chemistry, optical spectra, and relations to synthetic solid solutions

Ertl, Andreas; Hughes, John M.; Prowatke, Stefan; Rossman, George R.; London, David; Fritz, Eric A.

doi:10.2138/am-2003-8-921

Cited by 60 publications

(42 citation statements)

References 16 publications

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“…In addition to the Lundazi District of Zambia, significant occurrences of yellow Mn-rich elbaite are known from Tsilaisina in central Madagascar (Duparc et al, 1910), Elba Island in Italy (Bosi et al, 2005), Austria (Ertl et al, 2003(Ertl et al, , 2004, Nepal (Rossman and Mattson, 1986;Burns et al, 1994), the Malkhan District in Russia (Mashkovtsev and Zagorsky, 1997), and the Pamir Mountains in Tajikistan (Mashkovtsev and Zagorsky, 1997). Recently, substantial amounts of this tourmaline have come from the Muva area in Mozambique (unpublished data of BML and WBS).…”

Section: Discussionmentioning

confidence: 99%

Yellow Mn-Rich Tourmaline From The Canary Mining Area, Zambia

Laurs¹,

Simmons²,

Rossman³

et al. 2007

Gems & Gemology

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Section: Discussionmentioning

confidence: 99%

Yellow Mn-Rich Tourmaline From The Canary Mining Area, Zambia

Laurs¹,

Simmons²,

Rossman³

et al. 2007

Gems & Gemology

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“…The ROS tourmaline shows a slight zoning with the outer thin rim with a higher Mg number. However, the Codera CODp1 sample also contains yellow-green crystals of Mn-rich elbaite (Ertl et al 2003) and the graphic tourmaline from CODp2 shows thin rims evolving towards elbaite (with similar Mg number as the schorl core). Elbaitic compositions have been found in the Codera area and not in the miarolitic pegmatites of the Bodengo area.…”

Section: Niobium-tantalum-yttrium-rare Earth Elements (Ree)-uranium Omentioning

confidence: 99%

Tertiary Pegmatite Dikes of the Central Alps

Guastoni¹,

Pennacchioni²,

Pozzi³

et al. 2014

Can Mineral

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbSTRACTThe largest field of Alpine Oligocene pegmatite dikes is in the Central Alps within the Southern Steep Belt (SSB) of the Alpine nappes; it extends for about 100 km in an E-W direction and 15 km in a N-S direction north of the Periadriatic Fault, from the Bergell pluton (to the east) to the Ossola valley (to the west). The pegmatite field geographically overlaps (1) the highest temperature domain of the Lepontine Barrovian metamorphic dome and (2) the zone of Alpine migmatization. We have studied pegmatites in two areas: (1) the Codera area on the western border of the Bergell pluton and (2) the Bodengo area between the Mera and the Mesolcina valleys. Most pegmatites show a simple mineral assemblage consisting of K-feldspar, quartz, and muscovite ± biotite, and only a minor percentage of the dikes (< 5%) contains Sn-Nb-Ta-Y-REE-U oxide, Y-REE phosphate, Mn-Fe-phosphate, Ti-Zr-silicate, Be-Y-REE-U-silicate and oxide minerals (beryl, chrysoberyl, bertrandite, bavenite, and milarite), garnet (almandine-spessartine), tourmaline (schorl to rare elbaite), bismuthinite, magnetite, and rarely dumortierite and helvite. The mineral assemblages, geological context, and chemical compositions allow the distinction between LCT (lithium, cesium, tantalum) and mixed LCT-NYF (niobium, yttrium, fluorine) pegmatites (with only one exception of an NYF dike in the Bodengo area). The LCT pegmatites of the Central Alps did not reach a high degree of geochemical evolution. The most fractionated pegmatites are found in the Codera area and contain Mn-rich elbaite, triplite, pink-beryl, and Cs-Rb-rich feldspar. In the Bodengo area pegmatites locally contain miarolitic cavities and the most evolved pegmatites correspond to the berylcolumbite-phosphate type. From a structural point of view two main types of pegmatites can be distinguished: (1) pegmatites that were involved in ductile deformation and (2) pegmatites that postdated the main ductile deformation of the SSB. Many pegmatites of the Codera valley belong to the first structural type: they were emplaced at relatively high ambient temperature (ca. 500 °C) and locally show a pervasive recrystallization of quartz and a mylonitic structure. The Codera dikes trend about 70° and are steeply dipping. In the Bodengo area the main set of pegmatites (trending approximately N-S to NNE-SSW) crosscuts the ductile deformation structures of the SSB, but the area also includes an earlier generation of boudinaged and folded pegmatite dikes. The undeformed ...

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“…Fluorine was added as AgF, which decomposed during the experiments to release F (and formed MgF 2 and cryolite precipitates in some experiments). Although Ag normally alloys with the Au of the capsule tube when AgF decomposes, energydispersive X-ray analysis indicated that Ag was incorporated into the tourmaline crystals (as observed for synthetic Mn-rich dravite crystals by Ertl et al 2003b). Tourmaline with high Ag content coexisted with Ag oxide, Mg fl uoride, cryolite, and a presently unidentifi ed Na-Ni micaceous phase (in H 2 O-pressurized cold-seal vessels, Ni diffuses from the reaction vessel through the Au tubing and into the contents of the reaction assemblage).…”

Section: Tourmaline Synthesismentioning

confidence: 93%

Synthetic Ag-rich tourmaline: Structure and chemistry

London

Ertl

Hughes

et al. 2006

American Mineralogist

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Ag-rich tourmaline crystals were synthesized at 750 °C, 200 MPa H 2 O, and f O 2 = log (NNO) -0.5, starting with an oxide mix of dravite composition to which various reagents, including AgF and AgCl, were added. Tourmaline containing up to 7.65 wt% Ag 2 O was synthesized, and this is the fi rst time a tourmaline is described that contains signifi cant amounts of Ag at the ninefold-coordinated X site. Crystal structure refi nement and chemical analysis (EMPA) give the optimized formula X (Na 0.58 Ag 0.18 ■ ■ 0.24 ) Y (Al 1.54 Mg 1.46 ) Z (Al 5.34 Mg 0.66 ) T (Si 5.90 Al 0.10 )O 18 (BO 3 ) 3 V (OH) 3 W (O 0.53 F 0.47 ), with a = 15.8995(4) and c = 7.1577(4) Å, and R = 0.036 for a crystal (∼20 × 100 μm) with approximately 2.2 wt% Ag 2 O. Refi ning Na ↔ Ag at the X site clearly indicates that Ag occupies this site. The X-O2 distance of ∼2.52 Å is slightly longer than tourmaline with ∼(Na 0.6 ■ ■ 0.4 ), refl ecting the slightly larger ionic radius of Ag compared to Na. Releasing the occupancy at the Y site gives ∼Al 0.98 (∼12.7 e -), which can be explained by occupation of Mg and Al. On a bond-angle distortion vs. distance diagram, the Ag-rich olenite-dravite lies approximately on the V site = 3 (OH) line in the fi gure, defi ning the relation between bond-angle distortion (σ oct 2 ) of the ZO 6 octahedron and the distance. No H could be found at the O1 site by refi nement, in agreement with the Mg-Al disorder between the Y site and the Z site. Synthetic tourmaline contains no Ag when only AgCl is added; the compatibility of Ag in tourmaline, therefore, is largely a function of the F/Cl ratio of the fl uid medium. A positive association of Ag at the X site with Al at the Y site and with F suggests that tourmaline might be useful for exploration in Cornwall-type polymetallic ore deposits associated with F-rich peraluminous granites or at other Ag-, F-, and B-enriched deposits such as Broken Hill, Australia. Preliminary electron microprobe analyses of tourmaline from Cornwall and Broken Hill, however, failed to detect Ag at the 3σ detection level of 0.08 wt% Ag 2 O.

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Mn-rich tourmaline from Austria: structure, chemistry, optical spectra, and relations to synthetic solid solutions

Cited by 60 publications

References 16 publications

Yellow Mn-Rich Tourmaline From The Canary Mining Area, Zambia

Yellow Mn-Rich Tourmaline From The Canary Mining Area, Zambia

Tertiary Pegmatite Dikes of the Central Alps

Synthetic Ag-rich tourmaline: Structure and chemistry

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