American Mineralogist's Image Gallery

Matioliite: NaMgAl5(PO4)4(OH)6·2H2O

Comments: fiberous, blueish, matioliite aggregate on quartz.
Location: Gentil mine, Mendes Pimentel, Minas Gerais, Brazil. Scale: See Image.
© American Mineralogist

Matsubaraite: Sr4TiTi4Si4O22

Comments: Minute, dark grains of matsubaraite in a very pale green jadeite matrix.
Location: Itoigawa-Ohmi, Niigata Prefecture, Japan. Scale: Picture size 1 cm.
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Mazzite-Na: Na8Al8Si28O72?30H2O

Comments: Silky mazzite-Na fibers filling a cavity in basalt.
Location: Open pit of the U.S. Borax mine at Boron, California. Scale: Specimen size 5 mm.
© American Mineralogist

Medenbachite: Bi2Fe+++(Cu,Fe+++)(O,OH)2(OH)2(AsO4)2

Comments: SEM image of tabular plates of mendenbachite crystals. (AmMin, v81:505).
Location: Silicified barite vein from Reichenbach near Bensheim, Odenwald, Hesse, Germany. Scale: Scale Bar 20 µm.
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Melliniite: (Ni,Fe)4P  
Kamacite: alpha-(Fe,Ni)

Comments: Reflected-light image displaying an anhedral fragment of creamy-yellowish melliniite(1) associated with kamacite (2). AmMin, v91, p453.
Location: Northwest Africa 1054 acapulcoite. Scale: See Image.
© American Mineralogist

Melliniite: (Ni,Fe)4P  
Nickelphosphide: (Ni,Fe)3P

Comments: Reflected light image of creamy-yellowish melliniite (1) and nickelphosphide (3). AmMin, v91, p453.
Location: Northwest Africa 1054 acapulcoite. Scale: See Image.
© American Mineralogist

Menezesite: Ba2MgZr4(BaNb12O42)·12H2O

Comments: Brownish-red rhombododecahedral crystals of menezesite over calcite (with tiny black tochilinite inclusions). AmMin v93:82.
Location: Jacupiranga mine, in Cajati county, São Paulo state, Brazil. Scale: Crystal size 0.5 mm.
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Meridianiite: MgSO4·11H2O

Comments: Red arrow points meridianiite on the underside of a post in a frozen pond. Ice, in the form of snow covers the top of the post and the frozen pond surface (AmMin, v92:1757). This in an analoge for probable Martian occurrences.
Location: The ponds are on the Basque claims, which occur in a small valley in the Thompson region of central British Columbia. Scale: See Image.
© American Mineralogist

Meurigite-Na: [Na(H2O)2.5][Fe+++8(PO4)6(OH)7(H2O)4]

Comments: B&W image of sprays of meurigite-Na with turquoise, intergrown kidwellite/lipscombite, and crandallite on goethite. (AmMin, v94:720).
Location: Silver Coin mine, Valmy, Iron Point district, Humboldt County, Nevada, USA. Scale: Largest Spray = 1 mm.
© American Mineralogist

Meurigite-Na: [Na(H2O)2.5][Fe+++8(PO4)6(OH)7(H2O)4]

Comments: SEM image of meurigite-Na crystals. (AmMin, v94:720).
Location: Silver Coin mine, Valmy, Iron Point district, Humboldt County, Nevada, USA. Scale: See Image.
© American Mineralogist

Mimetite: Pb5(AsO4)3Cl  
Joelbruggerite: Pb3Zn3Sb+++++As2O13(OH)

Comments: SEM image of a barrel-shaped joëlbruggerite crystal lanced by acicular mimetite. (AmMin, v94:1012).
Location: Black Pine mine, 14.5 km northwest of Philipsburg, Granite County, Montana, USA. Scale: Crystal Size 30 µm across.
© American Mineralogist

Minasgeraisite-(Y): CaY2Be2Si2O10

Comments: SEM image of spherical aggregate of growth-zoned minasgeraisite crystals showing elongation along a and simple pedion termination. (AmMin, v71:603).
Location: Lawa de Sr. Jose Pinto pegmatite body, Jaguaracu, Municipo de Timoteo, Minas Gerais, Brazil. Scale: Tick Marks 10 µm.
© American Mineralogist

Moissanite: SiC

Comments: Gemmy, platy crystal of moissanite shown with largest (001) face. The arrow indicates a drop-shaped, black metallic inclusion. (AmMin, 88:1818).
Location: Found in a cobble at a beach along the Turkish coast of the Mediterranean Sea, around 150 km NW from Izmir, and is most likely derived from Tertiary volcanic rocks outcropping in the area. Scale: Scale bar 300 µ-m.
© American Mineralogist

Moissanite: SiC  
Silicon: Si

Comments: Backscattered electron image of metallic inclusion in moissanite (SiC). The gray shading in the BSE mage consists mainly of pure silicon (Si metal). The brighter areas are composed of Fe-silicide. (AmMin, 88:1818).
Location: Found in a cobble at a beach along the Turkish coast of the Mediterranean Sea, around 150 km NW from Izmir, and is most likely derived from Tertiary volcanic rocks outcropping in the area. Scale: Scalebar 200 µ-m.
© American Mineralogist

Mooihoekite: Cu9Fe9S16  
Haycockite: Cu4Fe5S8

Comments: B&W polished section image of mooihoekite-haycockite intergrowth showing tarnished mooihoekite (mh) and haycockite (hc). The small whitest lamellar grains are mackinawite.
Location: Hortonolite dunite (replacement,) pegmatite, Mooihoek Farm, Lydenburg District, Transvaal, South Africa. (AmMin, v57:689). Scale: See Image.
© American Mineralogist

Murataite: (Y,Na)6(Zn,Fe+++)5(Ti,Nb)12O29(O,F)14

Comments: Murataite (M) crystal in polished section showing cubic, form against quartz (Q). Other minerals are astrophyllite (A) and mineral Y (Y). (AmMin, v59:172).
Location: Small pegmatite in the St. Peters Dome area, El Paso County, Colorado, USA. Scale: See Image.
© American Mineralogist

Muthmannite: AgAuTe2

Comments: Backscattered scanning electron microphotograph of muthmannite (light gray) rimming a sylvanite (dark gray) grain. (AmMin 89:1506).
Location: Museum specimen from a gold-telluride deposit of Sacarîmb, Metaliferi Mountains, western Romania.. Scale: See Image.
© American Mineralogist

Mutnovskite: Pb2AsS3(I,Cl,Br)

Comments: SEM of blocky crystals of mutnovskite. Needle-like crystals of unknown Pb-Bi-As halogensulfosalts, currently under study, appear on the left. AmMin, v91, p22.
Location: Mutnovsky volcano, Kamchatka Peninsula, Russian Federation. Scale: See Image.
© American Mineralogist

Nchwaningite: Mn++2SiO3(OH)2·(H2O)

Comments: SEM image of acicular, platy nchwaningite crystals. (AmMin, v80:377).
Location: N'chwaning mine, Kalahari manganesefi eld, South Africa. Scale: See Image.
© American Mineralogist

Nesquehonite: Mg(HCO3)(OH)·2(H2O)

Comments: Scanning electron micrographs of nesquehonite clusters showing the typical elongated habit. (AmMin, 88:1882).
Location: Crystals associated with the remains of a saguaro, Carnegiea gigantea from south and west central Arizona. Scale: Scale Bar 50 µ-m (lower left).
© American Mineralogist