S. L. Penjield — Pyrite crystals from French Creek. 211 



which are so nearly alike that they can not be told apart, are 

 represented in fig. 4. Fig. 5 represents a crystal in the Be- 

 ment collection where the edges between the e faces at the 

 sides and r are replaced by a form x in the zone e, r. The x 

 faces are all rough and admit of only approximate measure- 



ment with the contact goniometer. The symbol was deter- 

 mined to be (6, 12, 7), 2-^. There are only eight of these faces 

 instead of the twenty-four which we should expect in an or- 

 dinary pyrite crystal. Fig. 6 represents a crystal in the Bement 

 collection in which the e faces are larger. This is the most 

 unsymmetrical of all the crystals ; on the side, which is turned 

 away from the observer, the e faces are so large that the front 

 and side ones just meet forming a solid angle and leaving none 

 of the middle edges between the lateral axes ; on the other 

 side, which is shown in the figure, the e faces are still larger 

 and the edges between them are replaced by the small s faces 

 231, 3-f. The s faces were bright and admitted of approxi- 

 mate measurements on the reflecting goniometer giving s *s, 

 231 a 231 = 30° 40', calculated 31° 0'. These s faces differ from 

 the ordinary pyrite combination, for with 210 and 021 usually 

 321, 132 and 213 occur in one octant, while here only one of 

 the alternating faces 231 occurs. 



All who have seen these crystals pronounced them the most 

 curious and interesting pyrite crystals that they have ever seen. 

 Why they 'have been distorted in this pecu- 

 liar way I cannot venture to say. Some law 

 must have governed them for they all have 

 such perfect, though lower than isometric, 

 symmetry. It is perhaps the result of the 

 vicinal development of the faces which is so 

 common at the locality. If in fig. 7, which 

 is the ordinary isometric trigonal-trisoctahe- 

 dron 332, f, the four r faces in front and 

 the corresponding ones behind were ex- 



