Ba8Com and, Goldschmidt — Anhydrite Twin. 48' 



Akt. XLYII. — Anhydrite Twin from Aussee ' by F. Bascom 

 and V. Goldschmidt. 



The subject of this paper is a twin crystal, obtained from 

 F. Krantz in Bonn by Mr. R. Schroeder. 



Description of Crystal. — The crystal is colorless and trans- 

 parent. Its dimensions are 15 mm : 13 mm : 5 mm . A twinning plane 

 divides the crystal into two nearly equal parts. Figure 1 

 shows both a top-view of the crystal, projected upon the plane 

 b = Ooo (010) of GoldschmidtVWinkeitabelle(WT),* and also 

 the crystal in perspective; figure 2 is a gnomonic projection of 

 the same with a similar orientation. 



Combination. — The forms present on the crystal are the 

 following : 



n f p 



12 13 15 (WT) 



i & i (projection on b) 



Of these forms r appears only as the twinning plane and 



* WT means here and in the following, — V. Goldschmidt, Krystallo- 

 graphische Winkeltabelle, 1897. 



a 



b 



c 



(r) 



o 







co 



oo 



10 



1 



oo 







Ooo 



00 



1 



