Common semiconductor materials include silicon, germanium and gallium arsenide. Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. Gallium trichloride is formed by the reaction of gallium metal with chlorine gas. Germanium or Indium gallium arsenide (InGaAs) detectors are commonly used. Gallium is also used in the production of artificial gadolinium gallium garnet for jewelry. One proposed material is indium gallium arsenide, or InGaAs. The primary photodetectors for telecommunications are made from Indium gallium arsenide. Indium phosphide-based cells have the potential to work in tandem with gallium arsenide cells. It is used standalone or together with gallium arsenide phosphide. This method is also used with semiconductor materials other than silicon, such as gallium arsenide. Blue gold is an alloy of gold and either gallium or indium. In the example of gallium and arsenic, single-crystal gallium arsenide is formed. CIGS is a I-III-VI compound semiconductor material composed of copper, indium, gallium, and selenium. LED development began with infrared and red devices made with gallium arsenide. The first single-chip gallium arsenide radar module was developed.