Palache — Notes on Tellurides from Colorado. 425 



twelve or more supposed goldschmidtite crystals from the 

 Little May Mine measured by him nor on the complex syl- 

 vanite crystals from the same region. In the absence of defi- 

 nite statements concerning the quality or frequency of occur- 

 rence of particular forms in the paper by Hobbs it is difficult 

 to- know what weight to assign to these forms, t, 292 and I, 

 161, are pyramids of the principal zone of sylvanite and may 

 well be good forms. The seven remaining forms are ortho- 

 domes. Of these, two, q, 203 and JT, 403 with its twin, x, 

 403 are probably good forms as they have simple symbols and 

 agree closely in angle with calculated position : 



Meas. Calcul. 



a, 203 /v 001 24° 37' 24° 20' 



X, 403 ^ 001 



42 34 



42 



36 



x, 403 twin ^ 001 



26 25 



26 



24 



v, 9-0-10, stands only 2° 20' from the dominant form 101 

 and may be vicinal to it ; r, 2'0 - 25, is inclined but 3° 10' to 

 001, of which it is very likely a vicinal ; y, 708, is inclined 

 3° 27' to 101 ' and may be vicinal to it ; lastly Z, 504 is 

 inclined 2° 16' to 403 and might be considered vicinal to that 

 form were it confirmed. 



It seems evident in the light of the above facts that so far 

 as crystallographic character is concerned goldschmidtite can 

 not be distinguished from sylvanite but represents a peculiar 

 habit of that mineral, common, as shown in the preceding 

 paper, to the sylvanite of Cripple Creek. Fig. 1 of the pre- 

 ceding paper on sylvanite illustrates fairly well the prevailing 

 habit of_goldschmidtite when in the sylvanite position, except 

 that <r, 121, should be very minute, and most crystals are 

 simple contact twins. 



The results of this study were submitted to Prof. Hobbs in 

 the hope that he might be able to complete them by a new 

 analysis of the type material on a larger amount of substance. 

 This proves unfortunately to be impossible, since the specimen 

 from which the type crystals were obtained was only tempo- 

 rarily in his hands and is not now available. 



In default of this analysis it was thought that it might be 

 worth while to determine the composition of the supposed 

 goldschmidtite from the Little May Mine, and by sacrificing 

 the whole specimen and carefully picking the crushed gangue 

 material enough was obtained (about - 4 gram) for an analysis. 

 This purpose was, however, defeated by an accident early in the 

 work, so that only the gold content could be determined. For 

 the sake of comparison this is given below together with that 

 of goldschmidtite and sylvanite. 



Little May Mine. Goldschmidtite. Sylvanite AuA.gTe 4 . Sylvanite Cripple Creek. 

 Au 28-89 31-44 24"45 26-09 



