﻿Jiidd 
  and 
  Hidden 
  — 
  Rxiby 
  in 
  North 
  Carolina. 
  381 
  

  

  slightly 
  developed. 
  A 
  few 
  crystals 
  were 
  examined 
  which 
  

   showed 
  only 
  the 
  presence 
  of 
  the 
  base, 
  the 
  rhombohedron 
  and 
  

   the 
  pyramid, 
  as 
  represented 
  in 
  iig. 
  8. 
  The 
  crystals, 
  measuring 
  

   up 
  to 
  7"™ 
  in 
  diameter, 
  were 
  doubly 
  terminated 
  and 
  nearly 
  per- 
  

   fect 
  in 
  their 
  development. 
  

  

  The 
  crystals 
  represented 
  by 
  fig. 
  7 
  are 
  similar 
  to 
  those 
  

   described 
  by 
  Max 
  Bauer"^ 
  from 
  the 
  Burma 
  district, 
  and 
  are 
  

   almost 
  identical 
  in 
  form 
  witli 
  a 
  sapphire 
  crystal 
  figured 
  by 
  the 
  

   author, 
  from 
  Emerald 
  Bar, 
  Canon 
  Ferry, 
  Magher 
  County, 
  

   Montana. 
  

  

  Although 
  both 
  the 
  basal 
  and 
  rhombohedral 
  planes 
  are 
  very 
  

   often 
  striated, 
  it 
  is 
  only 
  on 
  the 
  basal 
  planes 
  that 
  these 
  are 
  sharp 
  

   and 
  distinct 
  and 
  can 
  be 
  measured. 
  The 
  striations 
  are 
  parallel 
  

   to 
  the 
  three 
  intersections 
  of 
  the 
  base 
  c 
  with 
  the 
  rhombohedron 
  

   r, 
  as 
  shown 
  in 
  fig. 
  5. 
  

  

  A 
  very 
  common 
  development 
  that 
  was 
  noticed 
  in 
  nearly 
  all 
  

   the 
  flat 
  rhombohedral 
  crystals, 
  and 
  on 
  many 
  of 
  the 
  prismatic 
  

   crystals, 
  is 
  a 
  repeated 
  growth 
  on 
  the 
  basal 
  plane 
  of 
  the 
  rhom- 
  

   bohedron 
  r(lOll) 
  and 
  the 
  base 
  c(OOOl), 
  as 
  represented 
  in 
  figs. 
  1 
  

   and 
  6. 
  

  

  To 
  better 
  illustrate 
  the 
  variation 
  in 
  these 
  growths, 
  a 
  series 
  of 
  

   figures 
  (9 
  to 
  14) 
  have 
  been 
  drawn 
  in 
  basal 
  projection. 
  In 
  figs. 
  

   9 
  and 
  10, 
  which 
  represent 
  the 
  more 
  common 
  development 
  of 
  

   these 
  repeated 
  growths, 
  there 
  is 
  but 
  one 
  secondary 
  rhombohe- 
  

   dron 
  and 
  base, 
  which 
  sometimes 
  has 
  one 
  of 
  its 
  rhombohedron 
  

   faces 
  a 
  continuation 
  of 
  one 
  of 
  the 
  rhombohedron 
  faces 
  of 
  the 
  

   crystal. 
  Figs. 
  11 
  and 
  12 
  represent 
  repeated 
  growths, 
  the 
  faces 
  

   of 
  which 
  are 
  separate 
  and 
  distinct 
  from 
  each 
  other 
  and 
  from 
  

   the 
  faces 
  of 
  the 
  main 
  crystal. 
  In 
  the 
  crystals 
  represented 
  by 
  

   fig. 
  12, 
  when 
  the 
  secondary 
  growths 
  are 
  but 
  slightly 
  developed 
  

   the 
  basal 
  plane 
  of 
  the 
  crystal 
  has 
  the 
  appearance 
  of 
  being 
  

   striated 
  with 
  triangular 
  markings. 
  In 
  figs. 
  13 
  and 
  14 
  there 
  are 
  

   represented 
  a 
  series 
  of 
  growths 
  where 
  a 
  number 
  of 
  the 
  rhom- 
  

   bohedral 
  faces 
  coincide. 
  

  

  Some 
  of 
  the 
  pyramidal 
  crystals 
  (figs. 
  7 
  and 
  8) 
  also 
  showed 
  

   the 
  development 
  of 
  the 
  secondary 
  growth 
  of 
  rhombohedron 
  

   and 
  base. 
  

  

  The 
  thickness 
  of 
  the 
  rhombohedron 
  of 
  the 
  secondary 
  growth 
  

   varies 
  from 
  those 
  that 
  are 
  so 
  thin 
  that 
  they 
  appear 
  like 
  stria- 
  

   tions 
  to 
  some 
  that 
  are 
  2"'™ 
  thick. 
  

  

  This 
  same 
  style 
  of 
  development 
  has 
  been 
  described 
  by 
  Bauerf 
  

   as 
  occurring 
  in 
  the 
  Burma 
  rubies, 
  and 
  it 
  has 
  also 
  been 
  described 
  

   by 
  the 
  author;]: 
  as 
  occurring 
  on 
  the 
  Montana 
  sapphires. 
  

  

  A 
  few 
  crystals 
  were 
  observed 
  on 
  which 
  there 
  was 
  a 
  second- 
  

   ary 
  growth 
  parallel 
  to 
  the 
  prism 
  (1120). 
  

  

  * 
  Neues 
  Jahrb 
  Min.. 
  1896, 
  ii, 
  197. 
  f 
  Loc. 
  cit 
  , 
  p. 
  209. 
  

  

  % 
  This 
  Jouroal, 
  vol. 
  iv, 
  1897, 
  p. 
  42i. 
  

  

  