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Fe3+PO4 · 2H2O
Purple to reddish ...
Vitreous, Resinous
3½ - 4
Originally found by Alfred Lewis Oliver Legrand Des Cloizeaux in 1858, but designated "type I hureaulite". Named in 1890 by Willy Bruhns and Karl Heinrich Emil Georg Busz for its composition, being a PHOSPHate, and from the Greek σίδηρος "SIDERos" for iron. Alfred LaCroix intruced vilateite in 1910, while Duncan McConnel described clinobarrandite in 1940. Metastrengite was named by Palache, Berman, and Frondel in 1951 as the original phosphosiderite was described as a orthorhombic mineral.
Dimorph of:

Classification of Phosphosiderite

Approved, 'Grandfathered' (first described prior to 1959)

C : Phosphates without additional anions, with H2O
D : With only medium-sized cations, RO4:H2O = 1:2

4 : (AB)5(XO4)2·xH2O

19 : Phosphates
13 : Phosphates of Fe alone

Physical Properties of Phosphosiderite

Vitreous, Resinous
Diaphaneity (Transparency):
Transparent, Translucent
Purple to reddish violet, rose-red, peachy-pink, brownish yellow, moss-green, colourless; rose to colourless in transmitted light.
Hardness (Mohs):
3½ - 4
On {010}, good; on {001}, indistinct.
2.74 - 2.76 g/cm3 (Measured)    2.76 g/cm3 (Calculated)

Optical Data of Phosphosiderite

Biaxial (-)
RI values:
nα = 1.692 nβ = 1.725 nγ = 1.738
Measured: 62° , Calculated: 62°
Max Birefringence:
δ = 0.046
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
r > v, very strong
X = ^c ~ 4° = Light rose
Y = b = Carmine-red
Z = Colourless

Chemical Properties of Phosphosiderite

IMA Formula:
Fe3+PO4 · 2H2O
Elements listed in formula:
Common Impurities:

Crystallography of Phosphosiderite

Crystal System:
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 5.32 Å, b = 9.79 Å, c = 8.71 Å
β = 90.51°
a:b:c = 0.543 : 1 : 0.89
Unit Cell Volume:
V 453.62 ų (Calculated from Unit Cell)
Crystals tabular {010} or stout prismatic [001]. Also occurs as botryoidal or reniform masses and crusts with a radial-fibrous structure.
On {101}, commonly as interpenetration twins.

Occurrences of Phosphosiderite

Type Occurrence of Phosphosiderite

Relationship of Phosphosiderite to other Species

Other Members of Group:
KolbeckiteScPO4 · 2H2O
MetavarisciteAlPO4 · 2H2O
UM2005-02-AsO:AlHPScSiScAsO4 · 2H2O
8.CD.CastellaroiteMn32+(AsO4)2 · 4.5H2O
8.CD.05KolbeckiteScPO4 · 2H2O
8.CD.05MetavarisciteAlPO4 · 2H2O
8.CD.05UM2005-02-AsO:AlHPScSiScAsO4 · 2H2O
8.CD.10MansfielditeAlAsO4 · 2H2O
8.CD.10ScoroditeFe3+AsO4 · 2H2O
8.CD.10StrengiteFe3+PO4 · 2H2O
8.CD.10VarisciteAlPO4 · 2H2O
8.CD.10YanomamiteInAsO4 · 2H2O
8.CD.15ParascoroditeFe3+AsO4 · 2H2O
8.CD.20LudlamiteFe32+(PO4)2 · 4H2O
8.CD.25SterlinghilliteMn32+(AsO4)2 · 3H2O
8.CD.30RollanditeCu3(AsO4)2 · 4H2O
19.13.2StrengiteFe3+PO4 · 2H2O
19.13.4DufréniteCa0.5Fe2+Fe53+(PO4)4(OH)6 · 2H2O
19.13.5GiniiteFe2+Fe43+(PO4)4(OH)2 · 2H2O
19.13.6WhitmoreiteFe2+Fe23+(PO4)2(OH)2 · 4H2O
19.13.7TinticiteFe33+(PO4)2(OH)3 · 3H2O
19.13.8FerristrunziteFe3+Fe23+(PO4)2(OH)3 · 5H2O
19.13.9FerrostrunziteFe2+Fe23+(PO4)2(OH)2 · 6H2O
19.13.10BerauniteFe2+Fe53+(PO4)4(OH)5 · 6H2O
19.13.11VivianiteFe32+(PO4)2 · 8H2O
19.13.12MetavivianiteFe2+Fe23+(PO4)2(OH)2 · 6H2O

Other Names for Phosphosiderite

Other Information

Other Information:
Totally soluble in HCl, nearly insoluble in HNO3.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Phosphosiderite

Reference List:
Bruhns, Willy and Busz, Karl Heinrich Emil Georg (1890) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 17: 555.

Dana, Edward S. (1892) System of Mineralogy, 6th. Edition, New York: 823.

Lacroix, Alfred (1910) Minéralogie de la France et des ses colonies, Paris. 5 volumes: vol. 4: 477 (as Vilateite ?)

Goldschmidt, Victor (1920) Atlas der Krystallformen. 9 volumes, atlas, and text: vol. 6: 152.

Laubmann and Steinmetz (1920) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 55: 523.

Müllbauer (1925) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 61: 318.

De Angelis (1926) Ann. Mus. Civ. Stor. Nat. Genova: 52: 138.

Koechlin (1934) Centralblatt für Mineralogie, Geologie und Paleontologie, Stuttgart: 290.

McConnell, Duncan (1939) American Mineralogist: 24: 636.

Strunz and Sztrókay (1939) Zentralblatt Mineralien: 272.

McConnell, Duncan (1940) American Mineralogist: 25: 719 (as Clinobarrandite).

McConnell, Duncan (1943) Bulletin of the Geological Society of America: 54: 707.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 769-771.

American Mineralogist (1966): 51: 168.

Bolanz R. M., Wierzbicka-Wieczorek M., Giester G., Göttlicher J. & Steininger R. (2016): Structural incorporation of As5+ into phosphosiderite by a strengite/scorodite–like arrangement. ChemistrySELECT 1, 4152-4160.

Internet Links for Phosphosiderite URL:
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Localities for Phosphosiderite

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