SUI.PH ATI.S, CHROMATES, I1TC. 545 



chemi.-t Scheele, for whom it \v:is named. Tun^-ten i- Swedish 

 for heavy -tone, in reference to the hi<;h specific gravity of all the 

 mineral.- containing it. 



In occurrence, association, and artificial production, scheelite is 

 like wolframite, with which it is very closely associated, often being 

 a secondary mineral derived from it. 



Scheelite occurs at Chesterfield, Massachusetts; Caraharus 

 County, North Carolina; Mammoth district, Nevada; at Turn- 

 bull and 1 1 untington, Connecticut, and large crystals at Marlow, 

 Beauce County, Quebec. 



Stolzite is the lead tungstate isomorphous with scheelite. 



WULFENITE 



Wulfenite. Molybdate of lead, PbMo0 4 ; PbO = 60.7, 

 MoO 3 = 39.3; Tetragonal] Type, Tetragonal Polar; 6 = 1.5777; 

 001 A 101 =57 37'; 111 A 111 = 8022'; 102 A 102 = 76 31'; Com- 

 mon forms, n(lll), u(102), c (001), m(110), f (320) ; Cleavage, 

 111 good, e and s (113) less so; Brittle; Fracture, uneven; H. = 

 2.75-3 ; G. = 6.7-7 ; Color, various shades of yellow, red, or green ; 

 Streak, yellowish white ; Luster, adamantine to resinous ; Trans- 

 parent to translucent; a>r = 2.402; r = 2.304; <o = .098; 

 Optically (-). 



B.B. Fuses easily and boils. Reduced with soda on coal yields 

 lead buttons and a lead coat. In the S. Ph. bead it is yellowish 

 green in O. F., clear green in R. F. ; this bead shows molybdenum, 

 page 586. 



General description. Crystalline habit, tabular parallel to 

 the base ; combinations of the base with several pyramids, as at 

 the Red Cloud mine, Yuma County, Arizona ; or the base with 

 short prisms, as at Radersberg, Montana. The tabular crystals 

 are at times very thin and scaly. 



Wulfenite is interesting as an example of the tetragonal polar 

 type. Crystals from New Mexico show this polar development of 

 the pyramids, while crystals from Phoenixville, Pennsylvania, have 

 the upper and lower base unequally developed. 



Wulfenite is a secondary mineral associated with oxidized lead 

 ores. It is found only in small quantities, though in some localities 

 it occurs in sufficient amounts to constitute an ore of molybdenum. 



2N 



