Old samples - new amphiboles
2022 (Engelska)Ingår i: Abstracts, International Mineralogical Association 23rd General meeting, Lyon, 2022, Vol. 1, s. 42-42Konferensbidrag, Poster (med eller utan abstract) (Övrigt vetenskapligt)
Abstract [en]
The scientific value of old and well-preserved collections is priceless. Samples that already have been studied and described can still give very useful information. For instance, minerals with complex solid solutions like amphiboles sometimes show new compositions that are feasible because of crystal-chemistry and charge arrangements, based on the current classification scheme by Hawthorne et al. (2012) for the amphibole supergroup. In the last four years, a fruitful collaboration between the Swedish Museum of Natural History and the Department of Earth Sciences of the University of Milan has allowed the identification of new amphibole species, recognized by CNMNC-IMA. First of all, we identified hjalmarite, [ANaB(NaMn)CMg5TSi8O22W(OH)2], which is related to richterite via the homovalent substitution [B]Ca2+ → [B]Mn2+, and is the second recognized member of the sodium–(magnesium–iron–manganese) subgroup, after ferri-ghoseite. Sjögren (1891) had described a physically similar, MnO-rich sample from Långban, named “astochit”. A related amphibole, although belonging to a different subgroup, that we have formally described is potassic-richterite, [AKB(NaCa)CMg5TSi8O22W(OH)2]. It was found in a sample from the Pajsberg iron and manganese ore mines, which was originally collected by the mineralogist Lars Johan Igelström, probably in the 1850s. The most recent amphibole we have described is ferri-taramite [ANaB(NaCa)C(Mg3Fe3+2)T(Si6Al2)O22W(OH)2], found in a skarn sample from the Jakobsberg manganese mine: it was once examined by Flink (1914), who noted the unusual character of the amphibole and described it as a “strange hornblende”.
Ort, förlag, år, upplaga, sidor
Lyon, 2022. Vol. 1, s. 42-42
Nyckelord [sv]
amfibol, nytt mineral, mineralnomenklatur, Långban-typ, skarn
Nationell ämneskategori
Geologi
Forskningsämne
Den föränderliga jorden
Identifikatorer
URN: urn:nbn:se:nrm:diva-4856OAI: oai:DiVA.org:nrm-4856DiVA, id: diva2:1713566
Konferens
International Mineralogical Association 23rd General meeting, Lyon
2022-11-252022-11-252022-11-28Bibliografiskt granskad