phosphophyllite
/ˌfɒsfəʊˈfɪlʌɪt/Mineralogy
noun
A mineral of the monoclinic crystal system that is a hydrated phosphate of zinc and iron (often partly replaced by manganese), Zn2Fe(PO4)2.4H2O, and occurs as colourless to bluish-green, glassy, tabular crystals.
Origin
1920s; earliest use found in Mineralogical Abstracts. From German Phosphophyllit from phospho- + ancient Greek ϕύλλον leaf + German -it, so called in allusion to the mineral's perfect cleavage.