sets. The earliest color television CRTs had a poor-quality red; europium as a phosphor dopant made good red phosphors possible. Yttrium iron garnet (YIG) spheres have been useful as tunable microwave resonators. Rare earth oxides are mixed with tungsten
to improve its high temperature properties for welding, replacing thorium which was mildly hazardous to work with.
Today, those Indian and South African deposits still produce some rare earth concentrates, but they are dwarfed by the scale of Chinese production. China now produces over 95% of the world's rare earth supply.
The use of rare earth elements in modern technology has increased dramatically over the past years. For example,dysprosium
has gained significant importance for its use in the construction of hybrid car
Chinese export quotas have also resulted in a dramatic shift in the world's rare earth knowledge base. For example, the division of General Motors which deals with miniaturized magnet research shut down its US office and moved all of its staff to China