"Natrocarbonatite" is made up largely of two minerals, nyerereite (named after Julius Nyerere, the first president of independent Tanzania) and gregoryite (named after John Walter Gregory, one of the first geologists to study the East African Rift and author of the book "The Great Rift Valley"). These minerals are both carbonates in which sodium and potassium are present in significant quantities. Both are anhydrous, and when they come into contact with the moisture in the atmosphere, they begin to react extremely quickly. The black or dark brown lava and ash erupted begins to turn white within a few hours, then grey after a few days, then brown after a few weeks.