﻿Palache 
  and 
  Graham 
  — 
  Crystallization 
  of 
  Willemite. 
  639 
  

  

  Art. 
  LVI. 
  — 
  On 
  the 
  Crystallization 
  ■ 
  of 
  Willemite; 
  by 
  

   Charles 
  Palache 
  and 
  R. 
  P. 
  D. 
  Graham. 
  

  

  The 
  form 
  series 
  of 
  willemite 
  has 
  hitherto 
  been 
  small 
  and 
  

   few 
  accurate 
  measurements 
  of 
  its 
  crystals 
  have 
  been 
  recorded. 
  

   In 
  a 
  brief 
  note 
  in 
  this 
  Journal, 
  xxix, 
  1910, 
  one 
  of 
  the 
  authors 
  

   gave 
  observations 
  made 
  on 
  crystals 
  from 
  Franklin 
  Furnace, 
  

   .N. 
  J., 
  which 
  were 
  believed 
  superior 
  to 
  those 
  previously 
  obtained 
  

   and 
  proposed 
  a 
  new 
  axial 
  ratio 
  based 
  upon 
  them. 
  Crystals 
  

   from 
  the 
  same 
  locality 
  recently 
  secured 
  for 
  the 
  Harvard 
  Min- 
  

   eralogical 
  Museum 
  through 
  Mr. 
  Lazard 
  Cahn 
  give 
  a 
  far 
  better 
  

   series 
  of 
  measurements 
  as 
  well 
  as 
  a 
  number 
  of 
  forms 
  new 
  to 
  

   the 
  mineral, 
  and 
  it 
  is 
  the 
  purpose 
  of 
  this 
  paper 
  to 
  present 
  these 
  

   new 
  facts. 
  

  

  The 
  crystals 
  which 
  are 
  minute, 
  not 
  exceeding 
  a 
  millimeter 
  

   in 
  diameter, 
  are 
  of 
  prismatic 
  habit 
  and 
  perfectly 
  transparent, 
  

   colorless, 
  or 
  of 
  a 
  pale 
  yellowish-green 
  tint. 
  They 
  are 
  implanted 
  

   upon 
  rhodochrosite 
  which 
  is 
  in 
  part 
  gray 
  and 
  massive, 
  in 
  part 
  

   pale 
  pink 
  and 
  well 
  crystallized 
  in 
  curved 
  unit 
  rhombohedrons. 
  

   Most 
  of 
  the 
  crystals 
  are 
  singly 
  terminated, 
  but 
  several 
  were 
  

   noted 
  and 
  one 
  measured 
  which 
  showed 
  identical 
  characteristic 
  

   third 
  order 
  rhombohedrons 
  on 
  both 
  extremities 
  with 
  no 
  sug- 
  

   gestion 
  of 
  hemimorphism 
  as 
  indicated 
  for 
  the 
  mineral 
  by 
  Can- 
  

   field, 
  f 
  Many 
  of 
  the 
  crystals 
  on 
  these 
  specimens 
  are 
  dull 
  and 
  

   lusterless 
  by 
  reason 
  of 
  slight 
  etching 
  and 
  the 
  deposit 
  of 
  a 
  thin 
  

   coating 
  of 
  some 
  earthy 
  substance 
  upon 
  them. 
  But 
  the 
  meas- 
  

   ured 
  crystals 
  are 
  brilliant, 
  and 
  except 
  for 
  the 
  small 
  size 
  of 
  

   some 
  of 
  the 
  faces 
  leave 
  nothing 
  to 
  be 
  desired 
  in 
  the 
  quality 
  of 
  

   the 
  signal 
  reflections. 
  

  

  The 
  forms 
  observed 
  on 
  the 
  six 
  measured 
  crvstals 
  are 
  : 
  

  

  Letter 
  

  

  Symbol 
  

   G 
  2 
  

  

  Symbol 
  

   Bravais 
  

  

  Letter 
  

  

  Symbol 
  

   G 
  2 
  

  

  Symbol 
  

   Bravais 
  

  

  a 
  ■ 
  

  

  oo 
  

  

  (1120) 
  

  

  X 
  

  

  + 
  41 
  (I) 
  

  

  (3121) 
  

  

  m 
  

  

  00 
  

  

  (1010) 
  

  

  y 
  

  

  + 
  41 
  (r) 
  

  

  (2131) 
  

  

  r 
  

  

  + 
  1 
  

  

  (1011) 
  

  

  V 
  

  

  + 
  10-1(0 
  

  

  (7841) 
  

  

  *?i 
  

  

  — 
  2 
  

  

  (0221) 
  

  

  n 
  (?) 
  

  

  + 
  10-l(r) 
  

  

  (4371) 
  

  

  XL 
  

  

  10(0 
  

  

  (2113) 
  

  

  *d 
  

  

  - 
  24 
  (I) 
  

  

  (1232) 
  

  

  s 
  

  

  01(r) 
  

  

  (1123) 
  

  

  *D 
  

  

  - 
  H 
  (r) 
  

  

  (1322) 
  

  

  *o 
  

  

  + 
  21(Z) 
  

  

  (5143) 
  

  

  *q 
  

  

  -52 
  (I) 
  

  

  (1341) 
  

  

  *k 
  

  

  +#i(0 
  

  

  (4132) 
  

  

  *l 
  

  

  -74 
  (I) 
  

  

  (1561) 
  

  

  * 
  The 
  asterisk 
  indicates 
  new 
  forms, 
  

   f 
  This 
  Journal, 
  xxiii, 
  20, 
  1907. 
  

  

  