Production of beryllium and its compounds uses 4000–10,000 tons (3600–9000 metric tons) per year of the mineral beryl. The variant amounts of raw materials reflect wide differences in production rates for the beryllium industry. Beryl, a beryllium-aluminum silicate containing (in commercial grades) about 11–13% beryllium oxide (BeO), 17–19% aluminum oxide (Al₂O₃), 64–70% silicon dioxide (SiO₂), and 1–2% alkali metal oxides, is the only mineral used as a raw material for beryllium. Although beryl ore is widely dispersed throughout the world, it is not concentrated in deposits sufficient to justify direct mining.