Mineral: Fluorite on Quartz
Locality: Gerstenegg-Sommerloch tunnel, Gerstenegg, Grimsel area, Hasli Valley, Bern, Switzerland
Dimensions: 22,0 x 18,0 x 19,0 cm

Description: Main crystal size : 2,3 cm Bouquet of colorless quartz (the largest measuring 11.3 cm) partially covered with intact octahedral pink fluorite crystals. This sample was discovered in 1965 by the brother-in-law of Kaspar Fahner (first owner of this piece), then director of the Sommerloch tunnel project. The pink color is due to complex structural faults in the crystal network involving impurities such as YO2 groups. These defects seem to be formed at the relatively high temperature of 400 ° C. MIM number 1672 Photographer : Augustin de Valence (Ainu)

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