Formula: CaAl3(PO4)(PO3OH)(OH)6 hydrated phosphate
Specific gravity: 2.92
Colour: Yellow, white, gray; colourless in transmitted light.
Solubility: Soluble with difficulty in acids.
Crandallite is a secondary mineral that occurs in iron-rich, silica-poor
phosphate deposits and
as an alteration product in pegmatites
Crandallite may be found as a pseudomorph after gordonite (Dana).
Common impurities: Sr and Ba substituting for Ca and Fe3+ for Al (Dana).
In the phosphate deposits of South Australia crandallite is found as a replacement of other phosphate minerals, notably wavellite, also apatite, fluellite and minyulite (AJM 17.1.14).
At the Bone Valley Formation, Florida, USA, crandallite is associated with clay, millisite and wavellite (Dana).
At the Brooklyn Mine, Utah, USA, crandlallite is associated with quartz and baryte (Dana).
At Fairfield, Utah, USA, crandallite is associated with millisite, wardite, variscite, gordonite, englishite, montgomeryite, overite, kolbeckite and apatite (Dana).
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