The following uses for gallium are gathered from a number of sources as well as from anecdotal comments. I'd be delighted to receive corrections as well as additional referenced uses (please use the feedback mechanism to add uses).
- gallium wets glass or porcelain, and forms a brilliant mirror when it is painted on glass
- used for doping semiconductors and producing solid-state devices such as transistors
- gallium arsenide converts electricity into coherent light
- 90 tons of gallium (2 or 3 years of world production) is used to detect solar neutrinos by the use of the reaction: nu + 71Ga > 71Ge + e-. The rate, although very low (less than 1 interaction per day in 30 tonnes of Ga) makes gallium unique for this purpose. Two experiments are running : - GALLEX using 30 tons in the Gran Sasso underground laboratory (Italy) and SAGE with 60 tons in the Baksan laboratory in Caucasus (Russia). [thanks Michel]