Mineral Specimen Images (M)

Martinite: (Na,[ ],Ca)12Ca4(Si,S,B)14B2O38(OH,Cl)2F2·4(H2O)

Comments: Colorless, pseudohexagonal plate of martinite associated with sodalite and a clinoamphibole. (CanMin, v45:1281).
Location: Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada. Scale: Crystal size 40 µm.
© Canadian Mineralogist

Martyite: Zn3V2O7(OH)2·2H2O

Comments: Clusters of yellow flakes and coarser red-orange plates of martyite on V-U replacement of organic material.
Location: Blue Cap mine, near La Sal, San Juan County, Utah, USA. Scale: Picture size 1.4 mm.
© Canadian Mineralogist

Mascagnite: (NH4)2SO4

Comments: White, botryoidal mascagnite.
Location: Carola Mine, Freital, Dresden, Saxony, Germany. Scale: Picture size 6 mm.
© Thomas Witzke / Abraxas-Verlag

Mascagnite: (NH4)2SO4  
Lecontite: (NH4,K)Na(SO4)·2(H2O)

Comments: SEM BSE image of fine-grained lecontite (Le) and thenardite, occupying the space between mascagnite (M) crystals. CanMin 47:573.
Location: Coal-waste heap in Avion, northern France, that has been undergoing subsurface combustion for several decades. Scale: See Image.
© Canadian Mineralogist

Maslovite: PtBiTe  
Froodite: PdBi2  
Altaite: PbTe

Comments: Reflected light photomicrograph of maslovite (M), froodite (F), and altaite (A), in chalcopyrite matrix.
Location: Oktyabr'skoye Mine, Norilsk, Krasnoyarsk Territory, Siberia, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Massicot: PbO

Comments: Small nugget of reddish-yellow massicot.
Location: Wytheville, Wythe Co., Virginia, USA. Scale: 18x10x5 mm.
© John Betts - Fine Minerals

Massicot: PbO  
Litharge: PbO

Comments: Dark red litharge with brownish-yellow scaly massicot and white cerussite.
Location: Patagonia, Santa Cruz County, Arizona, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Masutomilite: K(Li,Al,Mn++)3[(Si,Al)4O10](F,OH)2

Comments: Transparent to translucent micaceous pale violet masutomilite with yellow iron stains.
Location: Hisu Kawa Mine, Gifu, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Masuyite: Pb[(UO2)3O3(OH)2]·3(H2O)

Comments: Bright reddish orange crystals of masuyite.
Location: Shinkolobwe mine, Tantara, Shaba, Democratic Republic of the Congo. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Masuyite: Pb[(UO2)3O3(OH)2]·3(H2O)

Comments: Dark reddish brown aggregate of masuyite with green metatorbernite on matrix.
Location: Musonoi mine, Kolwezi, Shaba, (Katanga), Congo (Zaïre). Scale: Picture size 2 mm.
© Paul M. Schumacher

Mathiasite: (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38

Comments: Mathiasite (M) exhibiting typical curvilinear cracks and incipient decomposition (upper left and lower right). Sample JFIS-I, Jagersfontein. Reflected light in air. (AmMin, v68:494).
Location: Metasomatized peridotites and heavy media concentrates from four kimberlites in the Republic of South Africa. Scale: Scale Bar 0.2 mm.
© American Mineralogist

Matildite: AgBiS2

Comments: Gray platy metallic crystalline matildite in white quartz.
Location: Sullivan Mountain, Montezuma District, Summit County, Colorado, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Matildite: AgBiS2  
Bismuth: Bi  
Bismuthinite: Bi2S3

Comments: SEM image of native Bi replaced by bismuthinite and matildite. Black areas represent gangue minerals. (CanMin, v43:899).
Location: Uranium deposit at Niederschlema-Alberoda, Germany. Scale: See Image.
© Canadian Mineralogist

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

Matlockite: PbFCl

Comments: Pale cream colored rosettes of matlockite crystals on matrix.
Location: Laurium, Greece. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

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.
© American Mineralogist

Mattagamite: CoTe2  
Altaite: PbTe  
Tellurantimony: Sb2Te3

Comments: Silvery metallic intergrowths of mattagamite with tellurantimony and altaite.
Location: Mattagami Lake Mine, Quebec, Canada. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Mattheddleite: Pb20(SiO4)7(SO4)4Cl4

Comments: Radial aggregates of colorless hexagonal microcrystals of mattheddleite with minor blue-green caledonite.
Location: Dry Smale Gill, Roughton Gill, Caldbeck Fells, Cumbria (Cumberland), England, United Kingdom. Scale: See Image.
© Rruff Database

Matulaite: CaAl18(PO4)12(OH)20·28(H2O)

Comments: Opaque white pearly crystalline matulaite coating on quartz and brown limonite.
Location: Bachman Iron Mine, Hellertown, Northampton County, Pennsylvania, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Maucherite: Ni11As8

Comments: Massive, fine-grained, dark maucherite with cream-colored barite.
Location: Eisleben, Mansfeld Basin, Saxony-Anhalt, Germany. Scale: Specimen size 8 cm.
© Thomas Witzke / Abraxas-Verlag