Hillebrand and Washington — Minerals from Utah. 305 





a. 



I. 



Hillebrand. 

 b. 



Mean. 



a. 



II. 



Pearce. 

 b. 



Theoretical 

 Compo- 

 sition. 



CuO .... 



. 62-34 



62-54 



62-44 



61-68 



61-22 



62-65 



ZnO 



0-06 



0-04 



0-05 















A.s 2 5 .-- 



29-59 



29-60 



29-59 



29-36 



28-85 



30-25 



P 2 5 _„_ 



0-05 



0-05* 



0-05 











h 2 o _:.: 



7-73 



7-72 



7-72 



7-31 



7-27 



7-10 



Fe 2 3 --- 



0-12 



0-12 



0-12 











Si0 2 



0-06 



0-06* 



0-06 















99-95 100-13 100-03 



98-35 



97-34 100-00 



These results reveal nothing worthy of remark except that 

 the water, as in most earlier analyses, is found uniformly higher 

 than that required by the formula 6CuO, As 2 6 , 3H 2 0, or 

 Cu 3 [As0 4 ] 2 +3Cu[OH} 2 . 



6. MlXITE. (?) 



On some specimens of ore, but apparently not in close asso- 

 ciation with the other minerals mentioned, was a mineral 

 occurring in delicate tufts of silky needles of a whitish to pale 

 geenish color as described by Mr. Pearce (1. c, p. 151, under 

 the title "New Mineral"). It was impossible to procure 

 enough of the needles free from an underlying non-crystallized 

 greenish coating of cavities for a satisfactory analysis. A good 

 deal of the latter was necessarily included in the sample tested, 

 but qualitative tests showed that both needles and coatings 

 contained the same constituents. It is hardly to be doubted 

 that both have the same centesimal composition. 



CuO 43-89 



ZnO 2-79 



CaO 0-26 



Bi 2 3 - 11-14 



As 2 5 --. 27-78 



P 2 5 0-06 



H 2 11-04 



Si0 2 0-36 



Fe 2 O s 0-97 



98-29 



Hillebranc 



. 



II. 



b 



Mean. 



Pearce 



43-88 



43-89 



50-50 



2-62 



2-70 







0-26 



0-26 



3-19 



11-22 



11-18 





28'79 



28-79f 



27-50 







0-06 







11-04 



11-04 



12.55 



0-48 



0-42 









0-97 









QQ-31 



QS-TA 



That an error as to the CuO occurs in Pearce's analysis is 

 beyond question. The above results agree fairly well with 

 Schraufs analysis of mixite,^: which contained 13-21 CuO, 

 13-07 Bi 2 3 , 30-15 As 2 6 , and 11-07 H 2 0, besides a little CaO 

 and FeO, but the form of this mineral as given by Schrauf dif- 

 fers from that of the present one, and its color is given as 



* Assumed the same as in a. 



| The higher value was undoubtedly nearer the truth than the lower. 



% Zeit. f. Kryst., iv, 277. 



