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1908-9. | CRYSTALLIZATIONS OF ERYTHRITE FROM COBALT. 443 
EVs PALLIZATION: OF ERYTHRITE FROM COBALT: 
By .W. F. GREEN,’ M.A,, 
Department of Mineralogy, University of Toronto. 
(Read 6th March, 1909). 
ERYTHRITE, or Cobalt Bloom, as it is commonly known, has 
* considerable interest connected with it, as it was the pink stain on the 
rocks that was associated with the first discovery of the mines in the 
famous Cobalt district. The Bloom found generally in the veins is the 
earthy variety and seldom shows good crystallization. Through the 
’ kindness of Messrs. J. W. Bain and A. L. Parsons, of the University of 
Toronto, I procured a specimen of well crystallized Erythrite. From 
this specimen were obtained a few crystals which were mounted and 
measured on a Goldschmidt two circle goniometer, to which method 
of measuring the appended numbers refer. 
‘ The crystals occur in the form of a druse and are attached to the 
matrix by one end of the vertical axis. They are small and when 
examined closely most of them are found to be a growth of thinner 
crystals in approximate parallel position. 
ELEMENTS. 
The axial ratio and the angle # are given by Goldschmidt in his 
Winkeltabellen for the Schneeberg crystals. The elements obtained 
from the Cobalt crystals are :— 
as Dees O.7 502: Ty = 017006 8=105°-O1" 
as compared with 
ens Ds Gas O. 7.5L 2:10:70 8 =105°-00° 
cited in Goldschmidt’s Winkeltabellen. 
FORMS. 
In all, seven forms were observed of which four are given in Gold- 
schmidt’s Tabellen and a fifth <1002 in Dana’s System of Mineralogy. 
The two new forms observed on the crystals examined are <1043 a 
very persistent large rough face and €3502 which occurs very plainly 
