﻿280 
  G. 
  Smith 
  — 
  Dyscrasite 
  in 
  Australia. 
  

  

  My 
  friend 
  Dr. 
  C. 
  A. 
  Anderson, 
  mineralogist 
  to 
  the~ 
  

   Australian 
  Museum, 
  Sydney, 
  has 
  kindly 
  made 
  an 
  exam- 
  

   ination 
  of 
  some 
  of 
  the 
  few 
  crystals 
  which 
  are 
  now 
  avail- 
  

   able 
  and 
  has 
  supplied 
  me 
  with 
  the 
  following 
  notes 
  : 
  

  

  "The 
  dyscrasite 
  is 
  sometimes 
  in 
  the 
  form 
  of 
  flattened 
  unter- 
  

   minated 
  prismatic 
  crystals 
  embedded 
  in 
  calcite 
  or 
  siderite, 
  

   strongly 
  striated 
  vertically, 
  and 
  irregularly 
  aggregated 
  into 
  par- 
  

   allel 
  and 
  subparallel 
  groups, 
  or 
  it 
  may 
  be 
  in 
  cylindrical 
  crystals, 
  

   the 
  faces 
  in 
  the 
  prism 
  zone 
  merging 
  into 
  one 
  another, 
  and 
  termi- 
  

   nated 
  by 
  the 
  basal 
  plane 
  or 
  by 
  a 
  globular 
  enlargement 
  on 
  the 
  

   apex. 
  Occasionally 
  the 
  crystals 
  are 
  pseudo-hexagonal 
  plates 
  

   tabular 
  on 
  the 
  base, 
  which 
  is 
  marked 
  with 
  stria? 
  running 
  parallel 
  

   to 
  its 
  outlines. 
  One 
  such 
  crystal, 
  about 
  7 
  mm. 
  in 
  diameter, 
  was 
  

   mounted 
  on 
  the 
  goniometer 
  and 
  approximate 
  measurements 
  were 
  

   obtained; 
  probably 
  the 
  forms 
  c 
  (001), 
  e 
  (Oil), 
  z 
  (112), 
  s 
  (133) 
  

   are 
  present, 
  but 
  the 
  angles 
  obtained 
  vary 
  considerably 
  and 
  the 
  

   forms 
  can 
  not 
  be 
  identified 
  with 
  certainty. 
  Another 
  habit 
  is 
  

   represented 
  by 
  a 
  granular 
  mass 
  of 
  very 
  small, 
  closely 
  aggregated, 
  

   equi-dimensional 
  crystals, 
  which 
  somewhat 
  resemble 
  rhombic 
  

   dodecahedra 
  in 
  shape, 
  but 
  all 
  the 
  faces 
  are 
  concave 
  and 
  quite 
  

   unsuitable 
  for 
  goniometric 
  determination." 
  

  

  The 
  discoveries 
  referred 
  to 
  were 
  made 
  during 
  1890- 
  

   1900. 
  The 
  mine 
  has 
  now 
  been 
  closed 
  down 
  for 
  several 
  

   years. 
  Up 
  to 
  the 
  time 
  of 
  my 
  retirement 
  from 
  its 
  man- 
  

   agement 
  there 
  was 
  no 
  reason 
  to 
  doubt 
  that 
  rich 
  ores 
  such 
  

   as 
  dyscrasite 
  and 
  fahlerz, 
  which 
  were 
  then 
  being 
  found 
  

   in 
  the 
  deepest 
  levels, 
  would 
  not 
  continue 
  downwards. 
  

   The 
  other 
  ores 
  referred 
  to, 
  however, 
  did 
  not 
  extend 
  to- 
  

   the 
  deeper 
  levels. 
  

  

  Sydney, 
  New 
  South 
  Wales, 
  

   Oct. 
  11, 
  1919. 
  

  

  