222 



W. E. Ford — Interesting Beryl Crystals. 



rounded and gave only approximate measurements, conse- 

 quently no definite symbols can be assigned to them. The 

 dihexagonal prism designated as 1, which appears on the crys- 

 tals and forms prominent faces in the pits, is close to a form 

 having (3140) as its symbol. The faces in the pits marked 1 

 are the same as the right hand prism face (3140), also marked 

 i, and reflect the light simultaneously with it; and those 

 marked 1' reflect together with the left hand prism face, 

 (4130), designated as V . The bottoms of the pits are usually 

 occupied by two small faces making a very acute angle with 

 one another which correspond to the two prism faces desig- 

 as 1" and 1"' ', flgure 9, which lie to the right and left 



beyond those marked 1 and 1' . Figure 11, which is a hori- 

 zontal section along the dotted line in figure 9, illustrates the 

 relations existing between the faces of the dihexagonal prism 

 and the corresponding faces found in the pits. The pyramid 

 of the first order, designated as #, which always forms the 

 upper and lower faces of the pits, approximates in its position 

 to (13'0 - 13*2). In addition to these faces the etchings show 

 two other forms, 3 and ^ which in their positions correspond 

 to the faces of dihexagonal pyramids. They are of vicinal 

 character, falling very close to the prism face m, as is shown 

 in the gnomonic projection, one averaging only 4° 57' and the 

 other 2° 13' from m. Because of the uncertainty of the meas- 



