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 Spaceflight offer to do so, hoping to raise the profile of engineering and aerospace in particular. During the 2007 Cambridge Science Festival, CU Spaceflight launched their Nova 5 balloon in front of a large crowd. CU Spaceflight CU Spaceflight is a student-run Cambridge University society founded with the aim of achieving cheap access to space. It is supported by the Cambridge-MIT Institute. The project was founded in the summer of 2006, with the specific goal of launching a rocket into space for less than GBP£1000. As of November, 2007, CU Spaceflight has launched five uncrewed high-altitude balloons, of which two were