"Watermelon" tourmaline from the Paprok mine (Nuristan, Afghanistan)
- Author(s)
- Andreas Ertl, Magdalena Dumanska-Slowik, Lucyna Natkaniec-Nowak
- Abstract
The "watermelon" tourmaline from the Paprok mine (Nuristan, Afghanistan) shows different tourmaline components. Four zones differ widely what is reflected by different chem. and various colors (pink core and green rim). All zones show a relatively low Mn content (.apprx.0.05 apfu) but different Fe contents. While Fe is in the (pink) core at the detection limit, it increases significantly in the outer (green colored) zones. In the core (zone I) "fluor-elbaite" could be identified for the first time for the Nuristan region. Tourmaline compns. of this zone show an elbaitic component of .apprx.55 mol%, .apprx.30 mol% rossmanite- and .apprx.15 mol% liddicoatite-component. Zone II shows an increasing schorl- and rossmanite-component (up to 40 mol%), while the liddicoatite- and elbaite-components are decreasing. The intermediate zone III shows the highest schorl-component of all zones (up to .apprx.11 mol%), while the elbaite-component is decreasing. In the rim (zone IV) the schorl-component decreases to .apprx.6 mol%, while simultaneously the elbaite-component increases. Our investigation shows that during tourmaline crystn. only the amts. of Fe and Li, which were available for the tourmaline crystn., have changed to a significant degree. We believe that at beginning of the crystn. of the Fe-bearing zones the formation of Fe-rich tourmalines (schorl, foitite) in this pegmatite was in a final stage and therefore in this pegmatitic system Fe increasingly was available. The Mn/(Mn+Fe) ration ranges from .apprx.0.10 to .apprx.1.00. The presence of different mineral inclusions such as stannite and Ca carbonates point to a hydrothermal origin of this tourmaline.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- AGH University of Science and Technology
- Journal
- Neues Jahrbuch für Mineralogie. Abhandlungen
- Volume
- 186
- Pages
- 185-193
- No. of pages
- 9
- ISSN
- 0077-7757
- DOI
- https://doi.org/10.1127/0077-7757/2009/0145
- Publication date
- 2009
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105116 Mineralogy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/f25e3d7a-d853-4f7b-ba95-219538389cea