Topaz pseudomorphs (Pyknit) after potassium feldspar –
Roman shaft, Altenberg tin mine, Saxon Ore Mountains, Germany
 
Honey-yellow pynite pseudomorphs after potassium feldspar, as up to 3.6 cm long “stem topaz” groups in a matrix of quartz and foliated black zinnwaldite mica, which surrounds a “core” of fine-grained greisen. An excellent and very representative cabinet sized specimen from the world-famous “Stockscheider” pegmatite cap of the Altenberg tin ore deposit! Historical find in 1968, from the exchange fund of the Bergakademie Freiberg/Saxony