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Formula:Mn2+Mn3+2(PO4)2(OH)2.4H2O
Hydrated phosphate containing hydroxyl, manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.84 to 2.85 measured 2.87 calculated
Hardness: 3½
Streak: Light red brown
Colour: Reddish-brown; yellowish brown to brownish red with red internal reflections in transmitted light
Solubility: Soluble in nitric acid
Environments
Bermanite is a late-stage secondary mineral replacing
primary phosphate
species, usually triplite or lithiophilite,
in complex granite pegmatites (Mindat, Webmin, HOM, AM 61.1241-1248).
Associated minerals include triplite,
strengite, leucophosphite,
hureaulite, lithiophilite,
stewartite, sicklerite,
rockbridgeite, phosphosiderite,
strunzite, switzerite and
paulkerrite (HOM, Mindat).
Bermanite is known only from pegmatites which contain oxidised and weathered masses of
lithiophilite, triphylite,
triplite, or other primary manganese-iron phosphates. Bermanite is one of the last
minerals to form during the weathering. It occurs lining seams and cavities and in small masses in the
primary mineral or in such
secondaries as rockbridgeite,
hureaulite, or sicklerite.
Phosphosiderite is usually associated with bermanite;
stewartite is somewhat less common. Bermanite alters to manganese oxides
(AM 52.1060-1066).
At a pegmatite along route 20, 5 miles west of Tanti, Prov. Crodoba, Argentina, bermanite occurs as an alteration product of
triplite. Thin crusts of
secondary bermanite are associated with
phosphosiderite, eosphorite, and a
black manganese oxide. Pachnolite has also been observed as white crusts and
as colourless crystals on bermanite (AM 53.416-431).
At the McMahon pegmatite near Olary, South Australia, bermanite replaces triplite along
fracture surfaces and occurs in association with phosphosiderite,
strengite, siderite,
hureaulite, rockbridgeite,
manganese oxides, and an unknown yellow fibrous mineral (AM 61: 1241–1248).
At the Sapucaia pegmatite, Minas Gerais, Brazil, bermanite occurs sparingly with
phosphosiderite coating barbosalite -
frondelite rock (AM 52.1060-1066).
At the Marivolanitra pegmatite, Mandrosonoro, Ambatofinandrahana, Madagascar, bermanite occurs with
phosphosiderite as an alteration of
triplite (AM 52.1060-1066).
At Mangualde, Portugal, bermanite has been found with phosphosiderite coating
stewartite and weathered lithiophilite
(AM 52.1060-1066).
At the Williams prospect, Coosa County, Alabama, USA, bermanite has been found intimately intergrown with
phosphosiderite and manganese oxides in
rockbridgeite - lipscombite
rock; in some specimens it has been found with stewartite and
strunzite as an alteration of hureaulite
(AM 52.1060-1066).
At the type locality, the 7U7 Ranch, Bagdad Mine area, Hillside, Eureka District, Yavapai county, Arizona, USA,
bermanite occurs in a granite pegmatite associated with
triplite, strengite,
phosphosiderite,
paulkerrite, leucophosphite
and hureaulite (AM 52.1060-1066, Mindat).
Near the Bagdad Copper Mine, about 25 miles west of Hillside, Arizona, USA, bermanite occurs in a pegmatite in narrow veins
crossing triplite (AM 21.656-661), of which it is an alteration product (AM 52.1060-1066).
At the Stewart Mine, Pala, California, USA, bermanite occurs with phosphosiderite,
stewartite and hureaulite on
lithiophilite and sicklerite
(AM 52.1060-1066).
At the Fletcher quarry, North Groton, New Hampshire, USA, bermanite occurs as crusts on
rockbridgeite, and as an alteration of
hureaulite with phosphosiderite
and stewartite (AM 52.1060-1066).
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