ganophyllite

{{Infobox mineral|boxbgcolor=#c79327| |image = Natural History Museum 139 (8047046589).jpg| name=Ganophyllite|category=Phyllosilicate minerals|formula=(K,Na,Ca)2Mn8(Si,Al)12(O,OH)32 · 8H2O| IMAsymbol = Gnp|strunz=09.EG.30|system=Monoclinic|dana=74.01.02.01|class=Prismatic (2/m)|symmetry=A2/a|unit cell=22,545.01|molweight=1,514.2|color=Brownish yellow to cinnamon brown|habit=Foliated micaceous|cleavage=Perfect on {???}|fracture=Brittle|mohs=4 - 4.5|luster=Vitreous|opticalprop=Biaxial(-)|refractive=nα = 1.537 nβ = 1.611 nγ = 1.613|birefringence=0.076|pleochroism=X = Pale yellow brown Y = Z = Dark yellow brown|dispersion=Weak|fluorescence=None|streak=Brownish yellow|gravity=2.84|density=2.84|diaphaneity=Transparent to transculent|impurities=Fe, Zn, Pb, Ca, Ba|other=25px Radioactive 3.87% (K)}}

Ganophyllite is a phyllosilicate mineral. It was named by Axel Hamberg in 1890 from the Greek words for leaf (φύλλον) and luster (γανωμα); the latter one was chosen due to the lustrous cleavages. The mineral was approved by the IMA in 1959, and it is a grandfathered mineral, meaning its name is still believed to refer to an existing species until this day. Tamaite is the calcium analogue, while eggletonite is the natrium analogue of said mineral.