Gwihabaite

Gwihabaite is a rare ammonium potassium nitrate mineral (NH₄,K)(NO₃). It is orthorhombic in form, colorless with a vitreous luster. It has a Mohs hardness of 5 and a specific gravity of 1.77. It is deliquescent and water-soluble. The mineral is also known as nitrammite. It was first described in 1996 for an occurrence in Gcwihaba Caves (Drotsky's Cavern, type locality), Maun, North-West District, Botswana. The spelling of the name was simplified, omitting the "c", which represents the "click" sound used by the San people. It occurs as incrustations and efflorescences on cave surfaces formed by bacterial action on bat guano.^[2][3]

Gwihabaite
General
Category	Minerals
Formula	(NH4,K)NO3
IMA symbol	Gwi[1]
Strunz classification	5.NA.15
Dana classification	18.01.03.01
Crystal system	Orthorhombic
Crystal class	Dipyramidal
Space group	Pmna (No. 62)
Unit cell	a=7.075Å, b=7.647Å, c=5.779Å, Z=4
Identification
Formula mass	85.31
Colour	White, colourless
Crystal habit	Acicular, Efflorescences
Cleavage	None
Mohs scale hardness	5
Luster	Vitreous
Streak	White
Diaphaneity	Transparent
Density	1.77
Birefringence	0.141
2V angle	87◦
Dispersion	None
Solubility	Soluble in H2O , deliquescent