




1891.] Mineralogy and Fetrography. 1009 

Penfield *! has analyzed an aurichalcite, occurring in narrow 
seams in an impure limonite from Utah, which yielded an average : 
CO; CuO ZnO HO Ca Des, 
16.36 19.37 53-09 9.92 61 3-57 = 2RCO,3R(OHR),, 
in which R = Zn and Cu, with CuO:Zno = 2:5. Inexhaustible beds 
of deauxtte have been discovered near Little Rock, Arkansas, and near 
Benton in the same state. According to Branner™ they are geneti- 
cally related in some unknown way with eruptive granites. The 
material is pisolitic in structure. A partial TESA of one specimen 
gave: ALO, = 35-64; SiO, = 10.38: FeO = 1.95'; TiO, == 3.50; 
Loss = 27.62. An inikas of ae aah Pitkin Co., Colo- 
rado, is given by Bailey as follo 
SO, ALO, Fe,O, FeO MgO H,O at 100° H,O at over 100° 
33°46 12098 t.60°% F18 -17 33-10 12.94 
Farrington™ has carefully examined the Arizona azurifes, on 
which he finds the new forms 2P, 4P, 3P3 and 42P$. Four distinct 
types of crystals are recognized ; one is pyramidal with 2P predomi- 
nant. The others are prismatic, dome-like, and lath-shaped. The 
latter came from the Longfellow Mine, and are peculiar for their 
ortho-diagonal elongation and the large development of the ortho- 
dome Pz. The axial relation calculated from the measurements of 
the different types isa: : c=.85676: 1: .88603 ; S=87°36'36” The 
very rare mineral pol/ucite has just been reported by Wells?” as asso- 
ciated with quartz crystals aud clay, and with psilomelane and a nearly 
colorless calcium beryl at Hebron, Maine. The pollucite is in 
irregular fragments, perfectly colorless, and as brilliant and transparent 
as plate glass. Its index of refraction for sodium light is 1.5247, and 
its density — 2.976—2.985. Its analysis gave: 
RO SiO, ALO, CaO Cs,O K,O Na,O = Li,O 
1.50 43.81") 26.36 22 36.10 -48 1.68 05 
corresponding to H,R’,Al,(SiO,),, with which formula all the analyses 
of the Elba mineral : may likewise be made to agree.——Columbite™ 
crystals from the Bob Ingersoll Claim and the Etta Mine in the Black 
Hills have a tabular habit with ooP-> predominating. Snow” re- 
ports the occurrence of furguotse at several ancient workings near 
Silver City, Grant Co., New Mexico. 





33 Amer. Jour. Sci., April, 1891, p. 296. 
% Tb., p. 300. « pee es 
3 Ib., p. 213. 
: - % Blake. Ib., Ma lay, wee 403. 
FA "1b, June, 1891, p. 5 



A E a IRN N EAA AT ERA W, IGN RE EEE R EEEO DA E 
