Albite

We purchased a collection about 9 years ago that included a few dozen specimens from the original Otto Pfordte collection (https://mineralogicalrecord.com/biographies_labels/pfordteotto/) . A flat we had buried in the warehouse revealed this piece. The specimens had been stored in a garage and the humidity , along with cockroaches, did in many of the labels. The specimen has glassy translucent crystals up to 1cm with a tabular habit and great coverage. One must assume (due to the collecting period of Mr Pfordte), that the specimen was found pre-20th century.

Locality: Riedertobel, Reusse Valley, Uri, Switzerland

Composition: an interconnected framework of three SiO₄ and one AlO₄ tetrahedra, with all oxygens shared between tetrahedra