128 



NEW YORK STATE MUSEUM 



TUNGSTATES. MOLYBDATES 



Wolframite (wolfram) (Fe,Mn)W0 4 



Wolframite is a tungstate of iron and manganese in which 

 these metals are present in varying amounts. 



The crystals are monoclinic, of the general type 

 shown in fig. 247. These are commonly tabular 



A-r^A 



parallel to the orthopinacoid; also prismatic. 

 Twins are quite frequent; granular or columnar 

 masses also occur. Perfect cleavage parallel to 

 the clinopinacoid is characteristic as well as part- 

 ing planes parallel to the orthopinacoid and hemi- 

 orthodome. The color is a dark grayish or brown- 

 ish black and the luster is submetallic. 



Wolframite occurs associated with tin ores and other metal- 

 lic minerals notably in the Cornwall and German mines. It 

 is also found in New South Wales and 

 Bolivia and in Connecticut, North Carolina. 

 Missouri and Dakota. 



It is used in the manufacture of tungsten 

 steel and as a source of the tungsten 

 salts, which are of considerable importance 



in dyeing. „ , 



J tt Scheelite CaW0 4 



Scheelite is a calcium tungstate crystallizing 

 in the pyramidal class of the tetragonal system. 



The crystals are pyramidal in habit (fig. 248), more rarely 

 tabular. These often occur in drusy crusts. The color is white 

 or light shades of yellow, brown, red, rarely green. The luster 

 is vitreous tending to adamantine. 



Scheelite occurs in crystalline rocks associated with cas- 

 siterite, fluorite, topaz, apatite, molybdenite or wolframite, in- 

 crusting or in quartz, and sometimes associated with gold. It 

 is of comparatively rare occurrence but is found at Monroe and 

 Trumbull Ct. and in South Carolina, Nevada, Idaho and 



Colorado. ,„ , 



Wulfenite PbMoO, 



Wulfenite is a lead molybdate crystallizing in the pyramidal 

 class of the tetragonal system. 



The crystals are commonly thin tabular in habit of the general 

 type shown in fig. 249; octahedral or prismatic forms are much 



