planchéite
/ˈplɑːnʃeɪʌɪt/ /ˈplanʃeɪʌɪt/ /ˈplɒ̃ʃeɪʌɪt/(also plancheite) Mineralogy
noun
A hydrated silicate and hydroxide of copper, Cu8Si8O22(OH)4.H2O, found in oxidized copper deposits in the form of blue, fibrous, translucent crystals of the orthorhombic system.
Origin
Early 20th century; earliest use found in Chemical Abstracts. From French planchéite from the name of J. Planche, French traveller and naturalist, who brought the first specimens of the mineral from the Congo + -ite.