Strengite is a relatively rare iron phosphate mineral with the formula: FePO4·2H2O.[5] The mineral is named after the German mineralogist Johann August Streng [de] (1830–1897).[6] Lavender, pink or purple in hue, it is similar to variscite[7] and is partially soluble, particularly in conditions where there is a low pH and low oxidation-reduction potential.[5] The color comes from ferric ion (Fe3+).[8]

Strengite
A small crystal of Strengite
General
CategoryMineral
Formula
(repeating unit)
FePO4·2H2O
IMA symbolStg[1]
Strunz classification8.CD.10
Dana classification40.04.01.02
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M Symbol: (2/m 2/m 2/m)
Space groupPcab
Identification
Formula mass186.85 g/mol
ColorColorless, pale violet, deep violet, red, carmine red, greenish white
Crystal habitBotryoidal, radial, spherical
Cleavage{010} Good, {001} Poor
Mohs scale hardness3.5–4
LusterVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity2.84
Density2.87 g/cm3
Optical propertiesBiaxial (+)
2V angle72° – 88°
Dispersionr < v, relatively strong
References[2][3][4]

References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Strengite Mineral Data". Webmineral.com. Retrieved 2011-10-25.
  3. ^ "Strengite mineral information and data". Mindat.org. Retrieved 2011-10-25.
  4. ^ "STRENGITE (Hydrated Iron Phosphate)". Retrieved 2011-10-25.
  5. ^ a b Patrick, W. H. Jr.; Gotoh, S.; Williams, B. G. (February 9, 1973), "Strengite Dissolution in Flooded Soils and Sediments", Science, 179 (4073): 564–565, Bibcode:1973Sci...179..564P, doi:10.1126/science.179.4073.564, PMID 17820817, S2CID 29895850
  6. ^ Senning, Alexander (2007), Elsevier's dictionary of chemoetymology: the whies and whences of chemical nomenclature and terminology, Elsevier, p. 374, ISBN 978-0-444-52239-9
  7. ^ Pough, Frederick H.; Peterson, Roger Tory (1997), A Field Guide to Rocks and Minerals, Peterson Field Guide, vol. 7 (5th ed.), Houghton Mifflin Harcourt, p. 239, ISBN 0-395-91096-X
  8. ^ "Minerals Colored by Metal Ions". minerals.gps.caltech.edu. Retrieved 2023-03-01.