What is "tangeite"

n. (context mineral English) A calcium, copper vanadate mineral, CaCu(VO₄)(OH)

Tangeite, also known as calciovolborthite, is a calcium, copper vanadate mineral with formula: CaCu(VO)(OH). It occurs as a secondary mineral that can be found in sandstone and also in the oxidized zones of vanadium bearing deposits.

It was named in 1925 by Aleksandr Evgenievich Fersman for its discovery locality in the Tange Gorge, Ferghana Valley, Alai Mountains, Kyrgyzstan.