Monday, May 5, 2008
The solution to the last implementation of my ongoing series called weekend fun is Zinnwaldite. Zinnwaldite is a rare member of the mica group containing lithium and iron. Nowadays used for the description of the series siderophyllite-polylithionite. It's occurence is limited to special granites, pegmatites and greisens. The paragenesis usually includes quartz, fluorite, feldspars, apatite and tin-minerals. The example shown is from the German side of the German-Czech border close to Sadisdorf or Altenberg (I didn't keep notes on private trips unfortunately). The type locality is a few km south in the Czech Republic and called Zinnwald/Cinovec in the Ore Mountains of Eastern Germany. To see some more and good fotos of Zinnwaldite go check out the Mineralienatlas.