Images
Formula: ZnFe3+2(PO4)2(OH)2.6.5H2O
Hydrated phosphate, strunzite group,
zinc-bearing mineral
Crystal system: Triclinic
Specific gravity: 2.66 measured, 2.679 calculated for the ideal formula, 2.655 calculated for the empirical formula
(Sitio do Castelo)
Hardness: 2½
Streak: White
Colour: Light brownish yellow (Sitio do Castelo), silvery white (Hagendorf-Süd)
Luminescence: Not fluorescent
Solubility: At room temperature, slowly soluble in dilute hydrochloric acid and rapidly soluble in concentrated
hydrochloric acid
Environments
Localities
There are two co-type localities, the Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab
District, Upper Palatinate, Bavaria, Germany and the Sítio do Castelo Mine, Folgosinho, Gouveia, Guarda, Portugal.
At the the Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate,
Bavaria, Germany, zincostrunzite occurs on the 67 metre level of the Cornelia mine opencut, where it was
collected from a 30 to 40 50 cm nodule of former triphylite that had been
replaced by vivianite,
phosphophyllite and minor
apatite. Zincostrunzite is found only in portions of crystals that
otherwise fall in the composition range of strunzite (or
ferristrunzite). These crystals occur as one of the youngest phases
in a cavity mostly containing somewhat altered phosphophyllite
crystals. Other secondary minerals found in the cavity
include chalcophanite,
strontium-bearing
fluorapatite, hopeite
(as epitactic overgrowths on phosphophyllite),
jahnsite, zinc-bearing
laueite, mitridatite,
parahopeite,
pseudolaueite,
scholzite–parascholzite,
schoonerite, stewartite and
whitmoreite–earlshannonite.
Goethite and cryptomelane are
also abundant in the oxidised zone.
The zincostrunzite makes up portions of needles that are up to about 5 mm long, forming bundles and divergent
sprays
(EJM 29.315-322).
The Sítio do Castelo Mine, Folgosinho, Gouveia, Guarda, Portugal, is well known for its diverse suites of unusual
secondary phosphate minerals, which have formed as the result
of intense weathering of primary
triplite–zwieselite,
fluorapatite and isokite in
association with sulphide minerals, such as sphalerite,
arsenopyrite and
chalcopyrite. Two types of
secondary phosphate assemblages occur in the deposit.
The first type is derived from the alteration of
triplite–zwieselite yielding,
in order of abundance, phosphosiderite,
strengite,
rockbridgeite–frondelite,
cacoxenite, bermanite,
beraunite, strunzite,
stewartite, laueite,
leucophosphite,
benyacarite, fluorapatite,
wavellite and kidwellite.
The second type is derived from the alteration of
triplite–zwieselite in
association with fluorapatite and
isokite yielding, in order of abundance,
ludlamite, vivianite,
strunzite, zinc-rich
rockbridgeite–frondelite,
manganese-rich
phosphophyllite,
hydroxylapatite,
jahnsite-(CaMnFe),
earlshannonite, lunokite
and plimerite.
The zincostrunzite occurs in vugs in the second type of
secondary phosphate assemblage on matrix composed of
triplite–zwieselite,
fluorapatite and
cryptomelane. Other minerals found in direct association with
zincostrunzite are cacoxenite,
plimerite, strengite and
strunzite. Zincostrunzite has been found as crystals that are
completely zincostrunzite as well as crystals that are mostly
strunzite, but with zincostrunzite rims
(EJM 29.315-322).
Zincostrunzite from the
Sítio do Castelo Mine - Image
Back to Minerals