﻿230 
  

  

  A. 
  P. 
  Honess 
  — 
  Etching 
  Figures 
  of 
  Beryl. 
  

  

  this 
  is 
  only 
  a 
  slight 
  modification 
  and 
  may 
  represent 
  a 
  different 
  

   stage 
  of 
  development, 
  or 
  a 
  potassium 
  solvent 
  slightly 
  different 
  

   from 
  that 
  used 
  by 
  the 
  writer. 
  The 
  figures 
  produced 
  by 
  the 
  

   writer 
  also 
  resemble 
  natural 
  etchings 
  found 
  on 
  the 
  second- 
  

   order 
  pyramid 
  of 
  a 
  light 
  green, 
  transparent 
  beryl 
  crystal 
  from 
  

   Topsham, 
  Maine. 
  The 
  figures 
  occurring 
  on 
  this 
  form 
  are 
  

   symmetrical 
  to 
  a 
  vertical 
  plane. 
  

  

  The 
  second-order 
  pyramid 
  was 
  not 
  well-developed, 
  con- 
  

   sequently 
  the 
  figures 
  obtained 
  are 
  rather 
  indefinite 
  but 
  resem- 
  

   ble 
  very 
  closely 
  those 
  produced 
  by 
  Traube 
  on 
  the 
  same 
  

   form. 
  They 
  are 
  elongated 
  oval 
  forms 
  (diagram 
  E), 
  extending 
  

  

  Fig. 
  13. 
  

  

  Dia.B 
  

  

  parallel 
  to 
  the 
  crystalline 
  edge 
  1120/1121, 
  widest 
  in 
  the 
  center 
  

   and 
  tapering 
  at 
  each 
  end. 
  Four 
  planes 
  comprise 
  the 
  figures, 
  

   the 
  two 
  larger 
  planes 
  meeting 
  in 
  the 
  bottom 
  of 
  the 
  pit 
  and 
  ex- 
  

   tending 
  almost 
  the 
  entire 
  length; 
  at 
  the 
  ends, 
  right 
  and 
  left, 
  a 
  

   small 
  face 
  descends 
  rather 
  abruptly 
  to 
  the 
  bottom. 
  The 
  figures 
  

   are 
  also 
  symmetrical 
  to 
  a 
  vertical 
  plane, 
  which 
  accords 
  with 
  

   the 
  symmetry 
  of 
  the 
  type. 
  Thus 
  the 
  four 
  forms 
  etched 
  serve 
  

   conclusively 
  to 
  illustrate 
  the 
  holohedral 
  character 
  of 
  beryl. 
  

  

  While 
  the 
  etch 
  figures 
  produced 
  by 
  the 
  separate 
  alkalic 
  

   hydroxides 
  are 
  distinctly 
  different, 
  those 
  produced 
  by 
  a 
  one 
  to 
  

   one 
  mixture 
  of 
  sodium 
  hydroxide 
  and 
  potassium 
  hydroxide 
  

   are 
  strikingly 
  similar 
  to 
  those 
  of 
  the 
  pure 
  sodium 
  fusion. 
  

   Solution 
  was 
  stopped 
  after 
  six 
  or 
  seven 
  seconds, 
  in 
  order 
  to 
  

   prevent 
  intergrowth, 
  hence 
  a 
  slight 
  difference 
  might 
  be 
  ex- 
  

   pected, 
  as 
  the 
  sodium 
  hydroxide 
  figures, 
  and 
  also 
  the 
  potassium 
  

  

  