Anhydrous phosphate containing hydroxyl, bjarebyite group
Specific gravity: 4.00 calculated
Streak: Greenish yellow
Colour: Brownish black, green-brown, black
Solubility: Slowly dissolved by cold hydrochloric acid (Dana)
Perloffite is a secondary mineral in complex zoned
At the Spring Creek Mine, Wilmington, South Flinders Ranges, Flinders Ranges, South Australia, perloffite is associated with baryte, copper and apatite (HOM).
At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, perloffite is associated with sphalerite crystals in a large mass of rhodochrosite - siderite after lithiophilite (R&M 94.6.513).
At the type Locality, the Big Chief Mine, Glendale, Keystone Mining District, Pennington county, South Dakota, USA, perloffite is a rare secondary mineral in a complex zoned granite pegmatite. It occurs as crystals on ludlamite, hureaulite and siderite, and in vugs in ludlamite formed from the hydration of triphylite (AM 62.1059, HOM).
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