Summary: A new hydrated aluminium phosphate mineral, kingite, from phosphate workings near Robertstown, South Australia, has an idealized formula Al₂O₃.Al(OH)₃.P₂O₅.9H₂O, with some replacement of OH by F. The specific gravity is 2·2 to 2·3, refractive index 1·514, and percentage chemical composition Al₂O₃ 31·92, P₂O₅ 28·63, H₂O 37·93. The three strongest lines on the X-ray diffraction pattern are 9·1, 3·45, and 3·48 Å. Kingite changes to a less hydrated phase between 154° C. and 163° C., which is also considered to be a new aluminium phosphate (meta-kingite) with idealized formula Al₂O₃.Al(OH)₃.P₂O₅.4H₂O. The strongest lines of its X-ray diffraction pattern are at 7·4, 5·02, and 37·19 Å.