Cadwaladerite

Cadwaladerite is a rare aluminium halide mineral with formula: AlCl(OH)₂·4(H₂O). It was reported for an amorphous substance associated with sulfate minerals and embedded in a halite crystal cluster. Its status is uncertain due to inadequate data.^[3][4][5] It was first described in 1941 for an occurrence in mine dumps of the Victoria Segunda mine Cerros Pintados, Iquique province, Tarapacá Region, Chile.^[4] It was named for Charles Meigs Biddle Cadwalader, president of the Academy of Natural Sciences.^[5] Lesukite was discredited (IMA2018-H).

Cadwaladerite
Yellow microcrystals and masses of the very rare aluminium chloride-hydroxide mineral Cadwaladerite from only one the three known localities worldwide: Maria Mine, Caleta Vítor District, Arica & Parinacota Region, Chile.
General
Category	Halide mineral
Formula	AlCl(OH)2·4H2O
IMA symbol	Cwd[1]
Strunz classification	3.BD.05
Crystal system	amorphous
Identification
Formula mass	168.51 g/mol
Color	Lemon yellow
Fracture	Conchoidal
Luster	Vitreous
Diaphaneity	transparent
Specific gravity	1.66
Optical properties	Isotropic
Refractive index	n = 1.513, variable
Other characteristics	deliquescent
References	[2][3][4][5]