of Chondrodite^ Humite and Chnohumite. 193 



The crystals were exceptionally fresh and pure, and showed 

 no trace of serpentinization. Some pure transparent pieces 

 were selected for analysis by hand picking, while crystals hav- 

 ing gangue attached to them were pulverized and separated 

 by the heavy solution, the powder that was used in the analy- 

 sis varying in specific gravity from 3*204 to 3*231. 



Chondrodite from JTafveltorp, Sweden. — The material for 

 our investigation was obtained from a specimen in the Brush 

 collection, Catalogue No. 2040. The crystals have a yellowish 

 brown color, are imbedded in sulphides, and 

 their habit as well as this unusual association 

 agree exactly with the description given by 

 Hj. Sjogren ;* the accompanying minerals 

 being chiefly galena and sphalerite with a 

 little chalcopyrite and amphibole. Only 

 fragmentary crystals could be separated from 

 the gangue, and the forms developed on one 

 of these is shown in fig. 2, which is a pro- 

 jection upon 010. Some of the measured 

 and calculated angles are : 



Measured. Calculated. 

 c ~r 2 , 001 a 125 = 53° 51' 54° 10' 

 r 2 *n, 125 a 121 = 27 38 27 37 

 U~r s , 121 a 123 = 31 45 31 39 



Measured. Calculated. 



.U, 010 a 121 = 26° 2-3/ 25° 58' 



ra 2 , 001 a 111 = 77 3 76 50 



,-re a , 111 a 111 = 26 18 26 40 



The material for analysis was separated by the heavy solu- 

 tion and varied in specific gravity from 3-252 to 3'265. 



Chondrodite from Mte. Somma, Italy. — Our material was 

 selected from a specimen in the 

 Brush collection, Cat. No. 2063, 

 which had been presented to 

 Prof. Brush by Prof. A. Scacchi. 

 The associated minerals constitut- 

 ing the gangue are calcite and 

 biotite (meroxene). The crystals 

 are honey-yellow in color, trans- 

 parent and present the forms shown in the basal projection, 

 fig. 3, the measured angles being : 



ei 





Measured. Calculated. 



Measured. Calculated. 



c a e 2 , 



001a 101 =70° 52' 



70° 56£' 



c a ro, 



001 a 125 = 54° 13' 



54° 10' 



C a — 6 2 , 



001 a 101 = 70 48 



70 56J 



c a r-i, 



001 a 127 =44 35 



44 41 



c a e lt 



001 a 103 =44 1 



43 59 



c a r 3 , 



001 a 123 =66 24 



66 34 



c a — ei, 



001 a 103 = 43 52 



43 59 



c a n, 



001 a 113 = 54 45 



54 56 



c a e a , 



001a 105 = 29 55 



30 4 



c a -n, 



001 a 113 = 54 54 



54 56 



C A Zi, 



001 a 012 = 57 24 



57 33 



c a n a . 



001 a 111 = 76 38 



76 50 



C ^ 2 a , 



001 a 014 = 38 4 



38 10-J 



C a — 7l a 



,001 a 111 = 76 46 



76 50 



*Zeitschr. Kryst., vii, p. 113, 1883. 



Am. Jour. Sci.— Third Series, Vol XLVII, No. 279.— March, 1894. 

 13 



