Hydrated normal phosphate, variscite group
Specific gravity: 2.57
Colour: Pale to emerald-green, bluish green, colourless to white, pale shades of brown or yellow, rarely red; Colourless to pale green in transmitted light.
Solubility: Insoluble in hydrochloric acid. Soluble in alkalis.
Common impurities: Fe,As
Variscite is typically deposited under surface conditions in cavities or breccias when phosphatic
meteoric waters act on aluminous rocks. Associated minerals include
The rare secondary mineral gordonite is sometimes formed from the alteration of variscite in nodules in limestone. (Dana).
At the phosphate deposits of the Mount Lofty ranges, South Australia, although uncommon, variscite has been found in several associations. At the Moculta quarry it is associated with opal and jarosite, and in cavities lined with apatite and associated with wavellite, beraunite and cyrilovite. It has also been found associated with cacoxenite, leucophosphite and pyrite, and with wavellite and minyulite.
At Tom's quarry variscite is associated with fluellite, leucophosphite, cacoxenite, wavellite and meurigite-Na in goethite-rich rocks. It has been found perched on minyulite and coating fluorapatite, fluellite and minyulite. In one part of the quarry nodules of variscite have been collected in a mudstone containing mica, tourmaline and rutile, and the variscite is partially altered to crandallite and associated with leucophosphite and childrenite.
At the Fairview workings variscite is associated with fluellite and at St John's quarry with leucophosphite and cacoxenite (AJM 17.1.26 ).
At the Mount Deverell variscite deposit, Milgun Station, Western Australia, variscite occurs as narrow veins that crosscut siltstone and mudstone as well as veins of quartz. The veins commonly have rims to 3 mm wide where the variscite has been partially altered to crandallite, foggite, quartz and/or wardite. The veins may be laterally altered and replaced by secondary minerals such as montgomeryite, hydroxylapatite, strengite and leucophosphite. Variscite also forms pseudomorphs after pyrite. The variscite deposits are hosted by marine sedimentary rocks (AJM 20.2.31).
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