Ferrimolybdite
(repeating unit)Fe3+2(MoO4)3·8(H2O) or Fe3+2(MoO4)3·n(H2O) IMA symbol Fmyb[1] Strunz classification 7.GB.30 Crystal system Orthorhombic Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Space group Pmmn Unit cell a = 6.665, b = 15.423
c = 29.901 [Å]; Z = 8 Identification Color Canary-yellow, straw-yellow, greenish yellow Crystal habit Acicular tufted to radial aggregates; powdery, earthy Cleavage Distinct on {001} Fracture Uneven Mohs scale hardness 1-2 Luster Adamantine, silky, earthy Streak Light yellow Diaphaneity Transparent to translucent Specific gravity 2.99 Optical properties Biaxial (+) Refractive index nα = 1.720 - 1.810 nβ = 1.730 - 1.830 nγ = 1.850 - 2.040 Birefringence δ = 0.130 - 0.230 Pleochroism X = Y = clear to nearly colorless; Z = dirty gray to canary-yellow 2V angle 26° to 32° (calculated) References [2][3][4]
H-M symbol: (2/m 2/m 2/m)
c = 29.901 [Å]; Z = 8
Ferrimolybdite is a hydrous iron molybdate mineral with formula: Fe3+2(MoO4)3·8(H2O)[3] or Fe3+2(MoO4)3·n(H2O).[2] It forms coatings and radial aggregates of soft yellow needles which crystallize in the orthorhombic system.
Discovery and occurrence
It was first described in 1914 for an occurrence in the Alekseevskii Mine in the Karysh River Basin, Khakassia Republic, Siberia, Russia.[2] It was named for its composition (ferric iron and molybdenum).
It occurs as an oxidation product of molybdenum bearing ore deposits. Associated minerals include: molybdenite, pyrite and chalcopyrite.[3]
References
- ^ 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.
- ^ a b c Ferrimolybdite on Mindat.org
- ^ a b c Ferrimolybdite on the Handbook of Mineralogy
- ^ Ferrimolybdite data on Webmineral.com
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