﻿234 
  A. 
  P. 
  lioness 
  — 
  Etching 
  Figures 
  of 
  Beryl. 
  

  

  at 
  right 
  angles. 
  This 
  seems 
  rather 
  suggestive, 
  for 
  may 
  we 
  not 
  

   assume 
  a 
  solvent 
  rich 
  in 
  soda, 
  and 
  is 
  it 
  not 
  probable 
  that 
  the 
  

   beryl 
  was 
  associated 
  with 
  rocks 
  and 
  minerals 
  with 
  a 
  high 
  

   sodium 
  content 
  % 
  At 
  least 
  the 
  form 
  of 
  the 
  figures 
  would 
  indi- 
  

   cate 
  this. 
  The 
  etchings 
  are 
  symmetrical 
  to 
  two 
  planes. 
  

  

  Pyramid. 
  — 
  The 
  second-order 
  pyramid 
  1121, 
  so 
  well 
  de- 
  

   veloped 
  on 
  this 
  crystal, 
  reveals 
  one 
  or 
  two 
  etched 
  faces. 
  The 
  

   figures 
  are 
  too 
  small 
  to 
  permit 
  of 
  detailed 
  study, 
  but 
  they 
  ap- 
  

   pear 
  as 
  top-shaped 
  forms, 
  with 
  the 
  point 
  downward 
  and 
  

   divided 
  symmetrically 
  by 
  a 
  vertical 
  groove 
  (diagram 
  B, 
  fig. 
  13). 
  

   They 
  are, 
  therefore, 
  symmetrical 
  to 
  a 
  vertical 
  plane. 
  

  

  Base. 
  — 
  The 
  figures 
  on 
  the 
  base 
  are 
  similar 
  to 
  the 
  natural 
  

   figures 
  on 
  the 
  North 
  Carolina 
  crystals, 
  with 
  the 
  exception 
  of 
  a 
  

   trigonal 
  form 
  (see 
  3, 
  diagram 
  F, 
  iig. 
  15). 
  The 
  base, 
  the 
  

   second-order 
  pyramid 
  and 
  the 
  unit 
  prism, 
  then, 
  reveal 
  the 
  

   symmetry 
  of 
  the 
  type, 
  as 
  illustrated 
  by 
  natural 
  etchings. 
  

  

  As 
  a 
  usual 
  thing 
  the 
  etch 
  figures 
  are 
  alike 
  upon 
  the 
  same 
  

   form 
  in 
  the 
  same 
  locality, 
  but 
  crystals 
  from 
  Miask, 
  Russia, 
  

   reveal 
  the 
  presence 
  of 
  two 
  different 
  solvents. 
  The 
  change 
  in 
  

   form 
  and 
  orientation 
  may 
  be 
  due 
  to 
  increase 
  in 
  concentration 
  

   or 
  temperature, 
  possibly 
  both, 
  but 
  very 
  evidently 
  there 
  has 
  

   been 
  a 
  decided 
  change 
  in 
  the 
  nature 
  of 
  the 
  solution, 
  for 
  the 
  

   difference 
  in 
  the 
  figures 
  is 
  not 
  only 
  orientation, 
  but 
  size 
  and 
  

   shape 
  as 
  well. 
  For 
  comparison 
  two 
  crystals 
  were 
  examined 
  

   and 
  described 
  ; 
  these 
  crystals 
  are 
  very 
  clear 
  and 
  a 
  greenish 
  

   yellow, 
  the 
  surfaces 
  being 
  very 
  bright 
  and 
  in 
  every 
  way 
  suitable 
  

   for 
  the 
  study 
  of 
  the 
  etchings 
  ; 
  they 
  are 
  of 
  the 
  same 
  size 
  and 
  

   similarly 
  developed 
  with 
  1010 
  as 
  the 
  dominant 
  form, 
  and 
  upon 
  

   this 
  face 
  the 
  figures 
  appear. 
  Upon 
  the 
  one 
  crystal 
  most 
  of 
  the 
  

   figures 
  are 
  hexagonal, 
  due 
  to 
  the 
  replacement 
  of 
  the 
  acute 
  

   angle 
  of 
  the 
  rhomb 
  by 
  a 
  small 
  face 
  lying 
  in 
  the 
  prism 
  zone 
  ; 
  

   the 
  larger 
  angle 
  is 
  approximately 
  a 
  hundred 
  and 
  thirty 
  -five 
  

   degrees 
  (diagram 
  C-I, 
  fig. 
  14). 
  Other 
  figures 
  occurring 
  on 
  the 
  

   same 
  face 
  are 
  very 
  shallow 
  and 
  perfectly 
  diamond-shape 
  in 
  

   outline. 
  The 
  pit 
  is 
  so 
  shallow 
  that 
  the 
  four 
  lateral 
  planes 
  are 
  

   reduced 
  to 
  mere 
  lines. 
  The 
  base 
  of 
  the 
  pit 
  is 
  very 
  large 
  and 
  

   also 
  diamond-shaped. 
  The 
  long 
  axis 
  extends 
  at 
  right 
  angles 
  to 
  

   the 
  prism 
  edges. 
  

  

  The 
  figures 
  of 
  the 
  second 
  crystal 
  are 
  diamond-shaped 
  ; 
  

   measuring 
  one 
  and 
  one-half 
  mm. 
  wide 
  and 
  three 
  mm. 
  long. 
  

   The 
  long 
  axes 
  of 
  the 
  figures 
  are 
  parallel 
  to 
  the 
  prism 
  edge, 
  the 
  

   reverse 
  of 
  the 
  position 
  of 
  the 
  figures 
  on 
  the 
  first 
  crystal. 
  

   Occasionally 
  the 
  obtuse 
  angle 
  is 
  replaced 
  by 
  a 
  curved 
  lateral 
  

   boundary, 
  producing 
  a 
  hexagonal 
  form 
  (diagram 
  C-II). 
  

   Although 
  these 
  crystals 
  are 
  from 
  the 
  same 
  locality 
  this 
  would 
  

   indicate 
  two 
  different 
  solutions. 
  As 
  to 
  the 
  nature 
  of 
  the 
  

   solvents, 
  the 
  writer 
  has 
  not 
  been 
  able 
  to 
  arrive 
  at 
  any 
  con- 
  

  

  