Tin-containing Andradite from Plavno Mine in the Krušné Hory Mts., Czechoslovakia

V. Dadák and F. Novák
Institute for Ore Research, Praha, Czechoslovakia
Institute of Mineral Raw Materials of Kutná Hora

Summary: Stannian andradite occurs with pyroxene and carbonates, with blende and pyrite as accessories in a skarn deposit in the Plavno mine, Krušné Hory Mts., NW. Bohemia. The green crystals are rhombic dodecahedra up to 3 cm in size. Sp. gr. 3·78; n 1·879; a 12·079±0·002 Å. Quantitative chemical and spectrographic analyses are given; the composition is (Ca2·96Mg0·04Mn0·02)3·02 (Fe1·793+Al0·18)1·97 (Si2·95Sn0·04)2·99O12. The content of tin (SnO2 1·07 %) is isomorphously bound in the lattice, and according to crystallochemical calculations the entrance of tin into the garnet lattice is most probably due to substitution of SnO44− for SiO44−. The presence of tin in the andradite shows that this element was already present in the metasomatic solutions during the process of skarnization.

Mineralogical Magazine; June 1965 v. 35; no. 270; p. 379-385; DOI: 10.1180/minmag.1965.035.270.11
© 1965, The Mineralogical Society
Mineralogical Society (www.minersoc.org)