542 MINERALOGY 



occurs at Cripple Creek, Colorado; in Mariposa County, Cali- 

 fornia ; near Morenci, Arizona. 



Alunogen, A1 2 (SO 4 )3 18 H 2 O, hydrous sulphate of aluminium, is 

 soluble in water and occurs as an efflorescence on the walls of coal 

 mines. Formed by the action of sulphuric acid on shales. A large 

 deposit, fibrous in character, occurs at Smoky Mountain, North 

 Carolina. 



Aluminite (A10) 2 SO 4 . 9 H 2 O, a basic sulphate insoluble in water, 

 is found in concretionary forms imbedded in clay. 



Kalinite, KA1(SO 4 ) 2 . 12 H 2 O, is a natural potash alum, found as 

 an efflorescence on slates and on the walls of caves of Tennessee. 



All these minerals where found in sufficient quantities are used in 

 the manufacture of soluble aluminium salts and alum. 



WOLFRAMITE 



Wolframite. Tungstate of iron and manganese, (Fe . Mn) W0 4 ; 

 when Fe : Mn: : 4 : 1, FeO = 18.9, MnO = 4.7, WO 3 = 76.4; 

 Monoclinic ; Type, Digonal Equatorial ; a : b : c = .8300 : 1 : 

 .8678 ; P = 89 21' = 001 A 100 ; 100 A 110 = 39 41' ; 001 A 101 = 

 45 56'; 001,011 =40 57'; Common forms, a (100), m(110), 

 t (102), y (102), o (111) ; Twinning axis c, composition plane, 100 ; 

 Cleavage, b perfect ; Brittle ; Fracture, uneven ; H. = 5-5.5 ; 

 G. = 7.2-7.5 ; Color, dark brown to nearly black ; Streak, brown- 

 ish or reddish to nearly black; Luster, metallic adamantine to 

 dull ; Opaque, rarely translucent. 



B.B. Fuses at three or four to a globule which in R. F. is 

 usually magnetic. When dissolved in the S. Ph. bead and reduced 

 with tin on coal yields a blue solution when dissolved in HC1. 

 Fused with soda in O. F. yields green sodium manganate. 



General Description. Crystals tabular with 100 prominent, 

 or stout prismatic, striated on 100 parallel to the vertical axis. 

 Also in granular masses. 



Wolframite is an isomorphous mixture of hiibnerite, MnWO 4 , the 

 tungstate of manganese, and ferberite, FeWO 4 , the tungstate of 

 iron. Hiibnerite occurs as brown, translucent, bladed crystals, while 

 ferberite is black and opaque. 



The three minerals occur under the same conditions, usually ii 

 quartz veins in granites, associated with sulphides ; here they have 

 probably been precipitated from hot solutions. They also occi 



