Jurbanite

Jurbanite is a sulfate mineral with the chemical formula AlSO₄(OH)·5H₂O. Its molecular weight is 230.13 g/mol. It crystallizes in the monoclinic system and is dimorphous with the orthorhombic mineral rostite.^[2] Jurbanite occurs as a secondary (post-mine) mineral in mines containing sulfide minerals.^[3]

Jurbanite
Jurbanite (field of view: 5 mm)
General
Category	Sulfate minerals
Formula	AlSO4(OH)·5H2O
IMA symbol	Jur[1]
Strunz classification	7.DB.15
Dana classification	31.9.10.1
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P21/n
Identification
Color	Colorless
Crystal habit	Small crystals and stalactitic forms
Tenacity	Brittle
Mohs scale hardness	2.5
Luster	Vitreous
Diaphaneity	Transparent
Specific gravity	1.786
Optical properties	Biaxial (-)
Refractive index	nα = 1.459 nβ = 1.473 nγ = 1.483
Birefringence	δ = 0.024
2V angle	Measured: 80°
Solubility	Soluble in water
References	[2][3][4]

Jurbanite was first described for an occurrence in the San Manuel mine of Pinal County, Arizona and first described in 1976s. It was named for Joseph John Urban, the mineral collector who discovered it.^[2]