dufrenite


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dufrenite

[dü′frā‚nīt]
(mineralogy)
A blackish-green, fibrous ferric phosphate mineral; commonly massive or in nodules.
References in periodicals archive ?
Dufrenite [Fe.sup.+2][Fe.sub.+3[(PO.sub.4)(.sub.3)[(OH.sub.5]*2H.sub.2O]
Thin fracture coatings and vug linings of botryoidal, dark green to black dufrenite have been observed very rarely, associated with radial sprays of strengite, minute cubic crystals of pharmacosiderite, and local sprays of meurigite.
Very rare clusters to 0.2 mm of radiating, pale yellow meurigite crystals associated with strengite have been discovered on selected dufrenite specimens.
The only arsenic-bearing species yet observed at the Willard mine, pharmacosiderite, has been found very rarely as pale yellow-green, isolated cubic crystals no larger than 0.1 mm on a few dufrenite specimens.
Dufrenite [Ca.sub.0.5][Fe.sub.6]([PO.sub.4]).sub.4][(HO).sub.6] [multiplied by] 2[H.sub.2]O
Hirson (1965) reported the presence of dufrenite in association with heterosite as an alteration product of triphylite but gave no further description.