Wulfenite

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called 'yellow lead ore'.Cluster of translucent, butterscotch-colored wulfenite blades from the Glove Mine of ArizonaA plate of very sharp, chocolate-brown crystals of wulfenite to 1.5 cm on edgeWulfenite from MexicoA rich jumble of tabular, reddish-brown wulfenite crystals fills the vug in the geode-like gossan matrix on this specimenWulfenite specimen from the Mina Ojuela, Mapimi, Durango, MexicoSpecimen from Ojuela Mine, Mapimí, Municipio de Mapimí, Durango, MexicoIntensely colored crystals to 1.7 cm, from Los Lamentos Mts (Sierra de Los Lamentos), Municipio de Ahumada, Chihuahua, MexicoA yellow crystal elongated on its sides, with a small attached cerussite in frontA classic cluster of butterscotch-colored wulfenite blades richly dusted with olive-green mimetite botryoidsWulfenite from Jianshan Mine, Xinjiang Autonomous Region, ChinaWulfenite from Tsumeb Mine (Tsumcorp Mine), Tsumeb, Otjikoto (Oshikoto) Region, NamibiaRed crystals of wulfenite Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called 'yellow lead ore'. It crystallizes in the tetragonal system, often occurring as stubby, pyramidal or tabular crystals. It also occurs as earthy, granular masses. It is found in many localities, associated with lead ores as a secondary mineral associated with the oxidized zone of lead deposits. It is also a secondary ore of molybdenum, and is sought by collectors. Wulfenite was first described in 1845 for an occurrence in Bad Bleiberg, Carinthia, Austria. It was named for Franz Xavier von Wulfen (1728–1805), an Austrian mineralogist. It occurs as a secondary mineral in oxidized hydrothermal lead deposits. It occurs with cerussite, anglesite, smithsonite, hemimorphite, vanadinite, pyromorphite, mimetite, descloizite, plattnerite and various iron and manganese oxides. A noted locality for wulfenite is the Red Cloud Mine in Arizona. Crystals are deep red in color and usually very well-formed. The Los Lamentos locality in Mexico produced very thick tabular orange crystals. Another locality is Mount Peca in Slovenia. The crystals are yellow, often with well-developed pyramids and bipyramids. In 1997, the crystal was depicted on a stamp by the Post of Slovenia. Lesser known localities of wulfenite include: Sherman Tunnel, St. Peter’s Dome, Tincup-Tomichi-Moncarch mining districts, Pride of America mine and Bandora mine in Colorado. Small crystals also occur in Bulwell and Kirkby-in-Ashfield, England. These crystals occur in a galena-wulfenite-uraniferous asphaltite horizon in a magnesian limestone. The wulfenite found in this area is similar in properties (paragenetic sequence, low silver and antimony contents of the galenas and absence of pyromorphite) to the wulfenites of the Alps and may be similar in origin. Wulfenite crystallizes in the tetragonal system and possesses nearly equal axial ratios; as a result, it is considered to be crystallographically similar to scheelite(CaWO4). Wulfenite is classed by a pyramidal-hemihedral (tetragonal dipyramidal) (C4h) crystal symmetry. Therefore, the unit cell is formed by placing points at the vertices and centers of the faces of rhomboids with square bases and the crystallographic axes coincide in directions with the edges of the rhomboids. Two of these lattices interpenetrate such that a point on the first is diagonal to the second and one quarter the distance between the two seconds.