Kalinite

Kalinite
Kalinite from the Virgin Valley District, Nevada, USA. Specimen size 5.4 cm
General
Category	Sulfate minerals
Formula (repeating unit)	KAl(SO4)2·11H2O
Strunz classification	7.CC.15
Dana classification	29.5.4.2
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/c
Unit cell	a = 19.92(16), b = 9.27(3) c = 8.304(13) Å β = 98.79(19)°; Z = 4
Identification
Formula mass	456.37 g/mol
Color	White to pale blue
Crystal habit	Fibrous
Fracture	Conchoidal
Mohs scale hardness	2 to 2.5
Luster	Vitreous
Streak	White
Diaphaneity	Transparent
Specific gravity	1.75 (observed) 2.0 (calculated)
Optical properties	Biaxial (-)
Refractive index	nα = 1.429 to 1.430, nβ = 1.452, nγ = 1.456 to 1.458
Birefringence	None
2V angle	52° (measured), 82° (calculated)
Solubility	Soluble in water
Other characteristics	Not fluorescent, barely detectable radioactivity
References

Kalinite is a mineral composed of hydrated potassium aluminium sulfate (a type of alum). It is a fibrous monoclinic alum, distinct from isometric potassium alum, named in 1868. Its name comes from kalium (derived from Arabic: القَلْيَه al-qalyah “plant ashes”) which is the Latin name for potassium, hence its chemical symbol, "K".

A proposal to remove recognition of kalinite as a mineral species is scheduled to be submitted to the International Mineralogical Association, currently (March 2010), kalinite is still on the list of approved minerals. Many older samples, however, have been found to be potassium alum.

Kalinite is a rare secondary mineral observed in the oxidized zone of mineral deposits, as efflorescence on alum slates, in caves, and as a volcanic sublimate. It is associated with jarosite, KFe³⁺₃(SO₄)₂(OH)₆, and cuprian melanterite (pisanite), (Fe²⁺,Cu²⁺)SO₄·7H₂O, at Quetena, Chile.