Crookesite Crookesite Crookesite is a selenide mineral composed of copper and selenium with variable thallium and silver. Its chemical formula is reported either as Cu(Tl,Ag)Se or (Cu,Tl,Ag)Se. It is formed by precipitation from hydrothermal fluids, and contains by mass: 16.3% Tl, 47.3% Cu, 2.9% Ag, and 33.6% Se. Crookesite is an opaque, bluish grey to pink toned brown metallic mineral crystallizing in the tetragonal system. It has a Mohs hardness of 2.5 to 3 and a specific gravity of 6.9. It was discovered in 1866 in Skrikerum, Sweden and named for Sir William Crookes (1832–1919), the discoverer of the element thallium.
¡Cu-Cut! the team of editors and illustrators continued their work at Catalan children's magazine "En Patufet". On the occasion of the first centennial of the closure of the magazine, the Barcelona City Historical Archive ("Arxiu Històric de la Ciutat de Barcelona") staged an exhibition and published a catalogue based on the once famous magazine. The exhibition was commissioned by Catalan cartoonist Jaume Capdevila ("Kap") and produced with the "Associació Tantatinta". ¡Cu-Cut! ¡Cu-cut! was a Catalan illustrated satirical magazine, written in Catalan. Published in Barcelona between 1902 and 1912, it followed the political line marked by Francesc Cambó's Lliga Regionalista. ¡Cu-cut!, named