Thortveitite
Ljosland 04, Knipan, Ljosland, Iveland, Agder, Norway
One of the largest and best thortveitites found in Norway. From Ljoslandsknipan, Iveland, Aust-Agder, Norway.
It's not a complete crystal, only a part of a larger one. The piece measures about 21 cm long. The crystal is a complex twin, on the prism {110}.
It was illustrated in fig.1, plate X in Brøgger, W.C, Vogt, Th. & Schetelig, J. (1922): ...
© Knut Edvard Larsen/NHM, Oslo