60 Ford — Clad copy rite Crystals from Arakawa, Japan. 



Figure 3 is an attempt to represent one of the crystals of 

 this type in its true proportions. The faces g, p^ and e, as is 

 shown, often are repeated many times at the ends of the 

 crystals ; g and p 1 by their oscillation with each other form at 



first a series of steps, but this soon results in simply fine striatum 

 lines which give a rounded appearance to the ends of the 

 crystals. The crystal represented by figure 3 is 17 mm in its 

 greatest length and 5 mm in height. Figure 4 is of a crystal 

 of the same general type but having the tendency to elongate 

 parallel to the diagonal axis greatly accentuated. The vertical 

 extension of a portion of the crystal as shown in the figure is 

 quite characteristic. This crystal is much smaller than the one 

 previously illustrated, its length being 16 mm and its height l'5 mm . 

 The length of the complete crystal however may have been 

 much greater, as the specimen is only terminated at one end, 

 the other being broken. 



Figure 5 represents a crystal which, while showing the same 

 forms as those already described and having some of the same 

 peculiarities of development, presents however quite a different 

 appearance. This is due chiefly to the absence of the upper 

 basal plane which was prominent. on the first type ; in this case 

 the crystal being terminated above by the faces of the pyramid 

 of the. second order e (101). All of the faces on this crystal 

 are striated on account of the oscillation of faces in the same 

 zone with each other, and in the case of ra and p^ no sharp 

 dividing line between them can be observed, one face yielding 

 gradually to the other. This crystal is the largest of the suite, its 

 greatest dimensions being 23 mm in length and 12 mm in height. 



Figure 6 is interesting as showing a crystal which combines 

 the two types described above. The larger crystals, like those 

 shown by figures 3 and 5, are bright in luster, being only 

 slightly tarnished, while the slender and smaller crystals, like 

 figures 4 and 6, are dull in color, being covered with a 

 greenish black deposit. 



Mineralogical Laboratory of tile Sheffield Scientific School 

 of Yale University, New Haven, Conn., 

 November, 1906. 



