Ford — Chaleopyrite Crystals from Araleawa, Japan. 59 



Art. YI. — Chaleopyrite Crystals from Arakawa, Japai 

 by W. E. Fokd. 



A small suite of unusually interesting chaleopyrite crystals 

 from Arakawa, Japan were recently presented to the Brush 

 Collection by Professor T. Wacla of Tokyo. The crystals 

 present no forms new to the mineral but show such unusual 

 habits of crystallization for chaleopyrite as to warrant a brief 

 description. The following forms were identified upon the 

 crystals ; c_(001), m (110), g (203), e (101), x (113), p (111), x, 

 (113),^ (lll),^' (312), s (513) ;the only quite rare form among 

 them being the tetragonal scalenohedron (312), which has 

 been designated by the letter f. This form has been previ- 

 ously observed by Sonheur on crystals from the Victoria Mine 

 near Burgholdingshausen, Siegen*. 



All of the different forms present on the crystals are 

 represented in an ideal combination in figure 1, which will also 



serve to illustrate one of the types of development. The 

 peculiar development of the crystals is brought about by the 

 entire suppression or the great subordination of half of the 

 faces of the forms c, x,p, m, and p x . This causes the crystals 

 to be greatly lengthened in the direction of one of the 

 horizontal diagonal axes and gives a prominent development 

 to the faces in the zone m, p, c, while the occurrence of only 

 one base causes the faces of the negative sphenoid^ to meet 

 in a sharp keel-like angle below. . Figure 2, which is_an ortho- 

 graphic projection upon aplane p arallel to m'" (110), of the. 

 ideal crystal represented in figure 1, has been introduced to 

 better illustrate this last peculiarity. Only the upper faces of 

 the various scalenohedral forms are to be found and they serve 

 to terminate the crystals at either end. 



*Zs. Kryst., xxiii, 545, 1894. 



