Ganophyllite

Ganophyllite
General
Category	Mineral
Formula (repeating unit)	(K,Na,Ca)2Mn8(Si,Al)12(O,OH)32 · 8H2O
Strunz classification	09.EG.30
Dana classification	74.01.02.01
Crystal system	Monoclinic
Crystal class	Prismatic (2/m)
Space group	A2/a
Unit cell	22,545.01 ų
Identification
Formula mass	1,514.2
Color	Brownish yellow to cinnamon brown
Crystal habit	Foliated micaceous
Cleavage	{???}Perfect
Fracture	Brittle
Mohs scale hardness	4 - 4.5
Luster	Vitreous
Streak	Brownish yellow
Diaphaneity	Transparent to transculent
Specific gravity	2.84
Density	2.84
Optical properties	Biaxial(-)
Refractive index	nα = 1.537 nβ = 1.611 nγ = 1.613
Birefringence	0.076
Pleochroism	X = Pale yellow brown Y = Dark yellow brown Z = Dark yellow brown.
Dispersion	Weak
Ultraviolet fluorescence	Non-fluorescent
Common impurities	Fe, Zn, Pb, Ca, Ba
Other characteristics	Radioactive 3.87% (K)

Ganophyllite's is a phyllosilicate mineral, whose name came from the Greek words leaf (φύλλον) and luster (γανωμα). It got named after Axel Hamberg in 1890. It is a member of Ganophyllite group, among with eggletonite and tamaite, and it is the potassium variety of eggletonite. It has a barely detectable potassium radioactivity. The formula includes potassium (K) if it is ganophyllite, eggletonite includes natrium (Na), and tamaite includes calcium (Ca) in their formula. It is pleochroic, which means the gem's color changes depending on the axis it is seen on, which is an optical phenomenon. On the X axis, it is seen in a pale yellow-brown color, and on the Y and Z axis, it can be seen as a dark yellow-brown gem. It has a barely detectable 1.8% radiation measured by GRapi (Gamma Ray American Petroleum Institute Units). It mostly consists of oxygen (47.02%), manganese (21.77%) and silicon (16.69%), but otherwise contains aluminium (5.88%), potassium (3.87%), which gives ganophyllite its irradiative attributes, magnesium (2.41%), hydrogen (1.6%) and sodium (0.76%).