Mineral Specimen Images (F)

Fedotovite: K2Cu++3(SO4)3O  
Dolerophanite: Cu2(SO4)O  
Chalcanthite: CuSO4·5(H2O)

Comments: Brown crystals of dolerophanite with blue chalcanthite and green fedotovite.
Location: Great Fissure (Main Fracture) eruption, Tolbachik volcano, Kamchatka Oblast', Far-Eastern Region, Russia. Scale: Picture size 3 mm.
© Thomas Witzke / Abraxas-Verlag

Fedotovite: K2Cu++3(SO4)3O  
Chalcanthite: CuSO4·5(H2O)

Comments: Green fedotovite with pale blue chalcanthite.
Location: Great Fissure (Main Fracture) eruption, Tolbachik volcano, Kamchatka Oblast', Far-Eastern Region, Russia. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Feinglosite: Pb2(Zn,Fe)[(As,S)O4]2·(H2O)

Comments: Feinglositc in polished section: (a) PPL light and (b) XPL light. In (a) note the inclusions of goethite (white) in the grey feinglosite (the black areas are holes). In (b) note the white to gray clusters of feinglosite. Black areas are goethite.
Location: Lining a cavity in a sample of massive chalcocite from Tsumeb, Namibia. (MinMag, v61:405). Scale: Picture Width 1 mm.
© Mineralogical Magazine

Feitknechtite: beta-Mn+++O(OH)

Comments: Brown feitknechtite with pink rhodonite.
Location: Ioi Mine, Ritto Cho, Shiga, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Feklichevite: Na11Ca9(Fe+++,Fe++)2Zr3Nb[Si25O73](OH,H2O,Cl,O)5

Comments: Brownish to purplish-brownish crystal of feklichevite.
Location: Kovdor Mine, Kovdor massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia. Scale: Picture size 6 mm.
© Thomas Witzke / Abraxas-Verlag

Felsobanyaite: Al4(SO4)(OH)10·5(H2O)

Comments: Gray white crystalline micro grains of felsöbanyaite on brown to yellow opal.
Location: Cavnik, Felsobanya, Maramures, Romania. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Fenaksite: (K,Na,Ca)4(Fe++,Fe+++,Mn)2Si8O20(OH,F)

Comments: Tan to rose colored crystalline fenaksite with dark green-black crystalline pyroxene.
Location: Khibiny Massif, Kola Peninsula, Murmansk District, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Fencooperite: Ba6Fe+++3Si8O23(CO3)2Cl3·H2O

Comments: Micro black needles of fencooperite in white sanbornite and pinkish gillespite matrix.
Location: Trumbull Peak, Sierra Nevada, Mariposa Co., California, USA. Scale: 2x2x2cm.
© Tom Loomis / Dakota Matrix

Ferberite: Fe++WO4

Comments: Ferberite with minor siderite selvage.
Location: Panasqueira (2nd level), in the region of Beira Baixa, Portugal. Scale: 6 x 5 cm.
© Fabre Minerals

Ferberite: Fe++WO4  
Anthoinite: AlWO3(OH)3  
Cerotungstite-(Ce): (Ce,REE)W2O6(OH)3

Comments: Yellow cerotungstite-(Ce), with black ferberite veins and whitish anthoinite.
Location: Bugarama, Rwanda. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ferchromide: Cr3Fe1-x(x=0,6)

Comments: Metallic microcrystal of ferchromide.
Location: Verkhneivinsk, Sverdlovsk District, Middle Urals, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ferdisilicite: FeSi2  
Fersilicite: FeSi

Comments: Dark grains of ferdisilicite, in sand, intermixed with dark grains of fersilicate.
Location: Poltava series, Zachativsk station, Donets (Donetsk) region, Donets'k Oblast' (Donetsk Oblast'), Ukraine. Scale: 0.2 cm field of view.
© Jeff Weissman / Photographic Guide to Mineral Species

Fergusonite-(Nd): (Nd,Ce)(Nb,Ti)O4  
Ferriallanite-(Ce): CaCe(Fe+++,Fe++,Al)3[SiO4][Si2O7]O(OH)

Comments: Orange-brown ferusonite-(Nd) grains in ferriallanite-(Ce) zone of the vein. Main black inclusions are ferriallanite-(Ce) crystals. White matrix is mixture of calcian strontianite and strontian calcite.
Location: Tornebohmite vein, Biraya Fe-REE ore occurrence, Biraya and Bya Rivers confluence area (Chara Basin), Vitim Plateau, Buriatia (Buryatia) Republic, Transbaikalia (Zabaykalye), Eastern-Siberian Region, Russia. Scale: FOV 1 cm.
© Pavel M. Kartashov

Fergusonite-(Y): YNbO4

Comments: Heavy mass of fergusonite-(Y) with one face polished flat to show the solid interior. Radioactive.
Location: Ambatofotsy, Betafo - Antsirabé region, Antananarivo Province, Madagascar. Scale: 6x2.5x1.5 cm.
© John Betts - Fine Minerals

Fergusonite-(Y): YNbO4  
Plumbopyrochlore: (Pb,Y,U,Ca)2-xNb2O6(OH)

Comments: Brown resinous fergusonite-(Y) (as per communication with Pavel M. Kartashov) with yellowish plumbopyrochlore.
Location: Ploskaya Mountain, Keivy Region, Kola Peninsula, Murmansk District, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Fergusonite-beta-(Ce): (Ce,La,Nd)NbO4

Comments: Dark brown vitreous amorphous (metamict) fragments of fergusonite-beta-(Ce).
Location: Amherst County, Virginia, USA. Scale: See Image.
© Rruff Database

Fergusonite-beta-(Y): YNbO4

Comments: Black crystal of fergusonite-β-(Y) in matrix.
Location: Fukushima City, Fukushima Prefecture, Japan. Scale: Crystal Size 6 mm.
© Nagashima mineral collection

Fermorite: (Ca,Sr)5(AsO4,PO4)3(OH)

Comments: Pinkish crystalline massive fermorite.
Location: Sitipar, Chindwara District, India. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Fernandinite: CaV8O20·4(H2O)

Comments: Greenish-yellow fernandinite coatings on sandstone.
Location: Deremo-Snyder Mine, Egnar, San Miguel County, Colorado. USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Feroxyhyte: Fe+++O(OH)

Comments: Brown botryoidal feroxyhyte.
Location: Pachi Limani, Laurium, Attiki, Greece. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species