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 London CU London CU London is a Higher Education institute owned and governed by Coventry University. CU London began offering courses to students in September 2017 and currently operates in the Dagenham Civic Centre in the London Borough of Barking and Dagenham. It is Coventry University's second campus in the capital alongside Coventry University London. CU London offers a range of subjects across Foundation, HNC, HND and degree level, which students can study full-time or part-time on evenings or weekends. Subjects offered by CU London include: Beyond its work teaching on undergraduate courses, CU London has continued to use its campus,