1912] Edkle: The Minerals of Tonopah, Nevada 15 



The measurements were fairly good, notwithstanding the 

 curvature of the main faces. 







Measured 



Calculated 



(5502) 



: (0552) 



106°30' 



106°44' 



(5505) 



: (0552) 



73 16 



73 13 



(1011) 



: (01T1) 



74 51 



74 55 



(1011) 



: (0552) 



53 39 



53 39 



(1011) 



: (01T2) 



37 26 



37 27 



(0552) : 



: (0111) 



112 15 



112 33 



Manganoealcitc. — Specimens of ore taken from the 1000-foot 

 level of the Belmont mine contain crystalline granular patches 

 of a light brown carbonate which turns dark brown when heated 

 and gives a strong reaction for manganese, but no iron. The 

 mineral is chiefly calcium carbonate containing manganese, but 

 the characteristic rose tint is missing. The grains of the mass 

 show some striated and curved faces and only the low rhombo- 

 hedron (0112) can be distinguished. 



Siderite is given by Spurr as one of the minerals of the veins 

 but none of the specimens include this carbonate. 



Rhodochrosite. — The manganese carbonate is of very rare 

 occurrence in the deposit. In the crevices of some of the quartz 

 specimens from the Montana-Tonopah mine a few pale rose 

 crystals of minute size occur singly. They are made up of the 

 steep scalenohedron y (3251) terminated by the base. The faces 

 of the scalenohedron are striated parallel to their basal edges 

 and the base is invariably dull. The crystals are shown in 

 figure 5, plate 1. 



Measured Calculated 

 (3231) : (5231) 45°37' 45°26' 



(3251) : (3521) 70 50 70 47 



Malachite and Azurite. — Small amounts of both copper car- 

 bonates occur as stains and crystalline coatings. The malachite 

 associated with the calcite of the Mizpah vein occurs in delicate 

 acicular groups. The azurite is with much of the malachite as 

 light blue earthy material. 



Silicates : Feldspar, Kaolinite, Sericite, and Rhodonite 



Feldspar and, Kaolinite. — The potash feldspar, classed as 

 adularia, is the prominent silicate of the gangue. It is all more 



