Wiktionary
zussmanite
n. (context mineralogy English) A hydrated iron-rich silicate, found as a pale green crystal with perfect cleavage.
Wikipedia
Zussmanite
Zussmanite (K(Fe,Mg,Mn)[AlSiO](OH)) is a hydrated iron-rich silicate mineral. Zussmanite occurs as pale green crystals with perfect cleavage.