Archerite

Archerite (IMA symbol: Aht^[1]) is a phosphate mineral with chemical formula (K,NH₄)H₂PO₄. It's named after Michael Archer (born 25 March 1945), professor of Biology, University of New South Wales. Its type locality is Petrogale Cave, Madura Roadhouse, Dundas Shire, Western Australia. It occurs in guano containing caves as wall encrustations and stalactites.^[2][3][4]

Archerite
Archerite (white) on a biphosphammite crystal
General
Category	Minerals
Formula	(K,NH4)H2PO4
IMA symbol	Aht
Strunz classification	8.AD.15
Dana classification	37.1.4.2
Crystal system	Tetragonal
Identification
Color	White
Cleavage	None
Fracture	Uneven
Tenacity	Brittle
Mohs scale hardness	1-2
Luster	Sub-Vitreous, Waxy, Greasy
Streak	White
Diaphaneity	Translucent
Specific gravity	2.23
Density	2.23 g/cm3