﻿A. 
  P. 
  lioness 
  — 
  Etching 
  Figures 
  of 
  Beryl. 
  235 
  

  

  elusions, 
  although 
  several 
  attempts 
  were 
  made 
  to 
  duplicate 
  the 
  

   figures 
  with 
  laboratory 
  preparations. 
  

  

  Perhaps 
  the 
  most 
  elaborate 
  figures 
  occur 
  on 
  a 
  beautiful 
  light 
  

   green 
  beryl 
  from 
  Topsham, 
  Maine. 
  The 
  crystal 
  possesses 
  

   three 
  of 
  the 
  fundamental 
  forms, 
  the 
  unit 
  prism, 
  the 
  base 
  and 
  

   the 
  pyramid 
  of 
  the 
  second 
  order, 
  and 
  all 
  faces 
  are 
  distinctly 
  

   etched. 
  

  

  Prism. 
  — 
  Upon 
  the 
  prism 
  three 
  stages 
  of 
  development 
  are 
  

   manifest 
  (figs. 
  9 
  and 
  10). 
  The 
  primitive 
  form 
  is 
  the 
  shallow 
  

   diamond-shaped 
  pit, 
  very 
  simple 
  and 
  distinct, 
  with 
  very 
  often 
  

   a 
  small 
  pit 
  in 
  the 
  center, 
  just 
  discernible 
  in 
  some 
  figures 
  and 
  

   quite 
  well 
  developed 
  in 
  others. 
  The 
  pit, 
  having 
  reached 
  an 
  

   advanced 
  stage, 
  completely 
  fills 
  the 
  diamond 
  form, 
  producing 
  a 
  

   second 
  stage 
  in 
  development. 
  The 
  mature 
  figure 
  possesses 
  a 
  

   deep 
  groove 
  at 
  right 
  angles 
  to 
  the 
  prism 
  edge 
  and 
  passes 
  the 
  

   entire 
  length 
  of 
  the 
  figure. 
  These 
  two 
  planes 
  as 
  they 
  ascend 
  

   quite 
  suddenly 
  diverge 
  at 
  a 
  much 
  larger 
  angle 
  and 
  intersect 
  

   the 
  surface 
  in 
  a 
  curved 
  line 
  and 
  in 
  some 
  cases 
  a 
  straight 
  line. 
  

   This 
  gives 
  the 
  figures 
  an 
  hexagonal 
  appearance, 
  elongated 
  at 
  

   right 
  angles 
  to 
  C 
  ; 
  the 
  acute 
  angles 
  at 
  the 
  ends 
  of 
  the 
  pit 
  

   measure 
  approximately 
  forty-five 
  degrees, 
  and 
  are 
  formed 
  by 
  

   the 
  intersection 
  of 
  two 
  small 
  faces, 
  lying 
  in 
  the 
  zone 
  of 
  the 
  

   second-order 
  pyramid 
  and 
  the 
  first-order 
  prism. 
  

  

  Base. 
  — 
  The 
  base 
  reveals 
  two 
  different 
  figures, 
  one 
  the 
  out- 
  

   growth 
  of 
  the 
  other 
  ; 
  one 
  is 
  hexagonal, 
  the 
  other 
  twelve-sided 
  

   and 
  both 
  regular 
  with 
  the 
  edges 
  of 
  the 
  hexagonal 
  form 
  par- 
  

   allel 
  to 
  0001/1120. 
  (See 
  4 
  and 
  5, 
  diagram 
  F.) 
  The 
  dihex- 
  

   agonal 
  figures 
  (fig. 
  12) 
  ultimately 
  become 
  hexagonal 
  as 
  was 
  

   observed 
  in 
  the 
  case 
  of 
  the 
  artificial 
  figures 
  produced 
  by 
  sodium 
  

   hydroxide 
  on 
  beryl, 
  where 
  the 
  figures 
  were 
  composed 
  of 
  so 
  

   many 
  small 
  faces 
  as 
  to 
  appear 
  circular, 
  but 
  which 
  gradually 
  

   became 
  hexagonal 
  as 
  solution 
  continued. 
  This 
  well-defined 
  

   figure 
  (fig. 
  12) 
  possesses 
  twelve 
  triangular 
  faces 
  meeting 
  in 
  a 
  

   common 
  point. 
  All 
  figures 
  on 
  the 
  base 
  are 
  symmetrical 
  to 
  six 
  

   vertical 
  planes. 
  

  

  Pyramid. 
  — 
  Upon 
  the 
  pyramid 
  of 
  the 
  second 
  order 
  are 
  three 
  

   or 
  four 
  well-defined 
  triangular 
  figures 
  ; 
  they 
  are 
  isosceles 
  

   triangles 
  with 
  the 
  large 
  angle 
  turned 
  upward 
  and 
  the 
  base 
  

   parallel 
  to 
  the 
  edge 
  1121/0001. 
  The 
  larger 
  forms 
  often 
  ap- 
  

   pear 
  pentagonal 
  (diagram 
  D, 
  -Q.^. 
  15) 
  and 
  all 
  are 
  symmetrical 
  to 
  

   a 
  vertical 
  plane. 
  

  

  The 
  artificial 
  etchings 
  produced 
  by 
  the 
  alkalie 
  fusions 
  are 
  

   represented 
  in 
  diagram 
  E, 
  where 
  the 
  relation 
  of 
  the 
  figures 
  to 
  

   the 
  crystalline 
  edges 
  may 
  be 
  observed. 
  Forms 
  on 
  1011 
  and 
  

   1121 
  are 
  produced 
  by 
  potassium 
  hydroxide 
  and 
  on 
  1010 
  and 
  

   0001 
  by 
  sodium 
  hydroxide. 
  

  

  