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 Coventry are also offered, designed to help students access higher education without traditional qualifications: CU Coventry CU Coventry is a subsidiary of Coventry University. It has been in operation since its launch in 2012, and was formerly known as Coventry University College. Its campus is located in the city of Coventry, England. It is part of CU, a network of three higher education campuses, comprising CU Coventry, CU London and CU Scarborough, all part of the Coventry University Group. These campuses offer an alternative, flexible approach to higher education to complement the traditional university experience of Coventry University and Coventry University