﻿236 
  A. 
  P. 
  Honess 
  — 
  Etching 
  Figures 
  of 
  Beryl. 
  

  

  Diagram 
  G 
  (fig. 
  15) 
  represents 
  the 
  natural 
  etchings 
  found 
  

   on 
  a 
  light 
  green 
  beryl 
  from 
  Mt. 
  Antero, 
  Chaffee 
  County, 
  

   Colorado. 
  The 
  figures 
  are 
  very 
  large 
  and 
  simple, 
  considerably 
  

   intergrown, 
  but 
  occasional 
  individuals 
  may 
  be 
  readily 
  detected 
  

   with 
  the 
  unaided 
  eye. 
  The 
  more 
  common 
  type 
  of 
  etching 
  is 
  

   represented 
  by 
  1 
  and 
  2 
  of 
  diagram 
  G-. 
  In 
  every 
  figure 
  there 
  is 
  

   present 
  the 
  two 
  long 
  faces 
  lying 
  in 
  the 
  prism 
  zone, 
  which 
  

   either 
  intersect 
  at 
  the 
  base 
  of 
  the 
  figure, 
  or 
  extend 
  downward, 
  

   intersecting 
  the 
  third 
  long 
  face, 
  forming 
  the 
  bottom 
  of 
  the 
  pit. 
  

   Very 
  often 
  the 
  larger 
  figures 
  possess 
  narrow 
  depressed 
  areas 
  

   extending 
  lengthwise 
  the 
  pit 
  and 
  which, 
  when 
  observed 
  in 
  

   number, 
  give 
  the 
  crystal 
  face 
  a 
  striated 
  appearance, 
  parallel 
  

   to 
  C. 
  The 
  small 
  face 
  at 
  each 
  end 
  may 
  or 
  may 
  not 
  be 
  present. 
  

   The 
  figures 
  are 
  symmetrical 
  to 
  two 
  planes 
  at 
  right 
  angles* 
  

  

  A 
  few 
  well-defined 
  natural 
  etchings, 
  which 
  were 
  observed 
  

   on 
  the 
  base 
  of 
  a 
  light 
  green 
  beryl, 
  from 
  Mursinka, 
  Siberia, 
  are 
  

   shown 
  in 
  ~B.g. 
  11. 
  

  

  Hence 
  the 
  various 
  forms, 
  naturally 
  etched, 
  conform 
  to 
  the 
  

   symmetry 
  of 
  the 
  type. 
  And 
  from 
  the 
  foregoing 
  investigation, 
  

   it 
  is 
  readily 
  observed, 
  that 
  the 
  etch 
  figure, 
  be 
  it 
  produced 
  in 
  

   nature 
  or 
  in 
  the 
  laboratory 
  by 
  solutions 
  of 
  various 
  constituents, 
  

   concentrations 
  and 
  temperatures, 
  the 
  result 
  is 
  always 
  an 
  

   accurate 
  outward 
  reflection 
  of 
  the 
  interior 
  structure 
  of 
  the 
  

   crystal. 
  

  

  Princeton 
  University, 
  

   Princeton, 
  N. 
  J. 
  

  

  