﻿Penfield 
  and 
  Warren 
  — 
  Composition 
  of 
  Parisite. 
  21 
  

  

  Art. 
  III. 
  — 
  On 
  the 
  Chemical 
  Composition 
  of 
  Parisite 
  and 
  a 
  

   new 
  occurrence 
  of 
  it 
  in 
  Ravalli 
  Co.^ 
  Montana 
  / 
  bj 
  S. 
  L. 
  

   Penfield 
  and 
  C. 
  H. 
  Warren. 
  

  

  Eecently 
  Mr. 
  Lazard 
  Calm 
  of 
  J^ew 
  York 
  sent 
  to 
  the 
  

   Mineralogical 
  Laboratory 
  of 
  the 
  Sheffield 
  Scientific 
  School 
  for 
  

   identification, 
  several 
  specimens 
  from 
  Montana, 
  showing 
  crys- 
  

   tals 
  of 
  an 
  unusual 
  appearance. 
  These 
  proved 
  to 
  be 
  the 
  rare 
  

   mineral 
  j)arisite, 
  hitherto 
  observed 
  only 
  in 
  small 
  amount 
  at 
  the 
  

   original 
  locality, 
  the 
  emerald 
  mines 
  of 
  the 
  Muso 
  Yalley, 
  United 
  

   States 
  of 
  Columbia 
  ; 
  sparingly 
  at 
  Ober 
  Aro, 
  Langesundfiord, 
  

   Norway;"^ 
  and 
  quite 
  recently 
  the 
  mineral 
  has 
  been 
  found 
  at 
  

   Xarsasuk 
  in 
  Southern 
  Greenland. 
  A 
  brief 
  note 
  on 
  its 
  occur- 
  

   rence 
  at 
  the 
  latter 
  locality 
  was 
  made 
  by 
  Gust. 
  Flink 
  in 
  the 
  

   report 
  of 
  a 
  trip 
  made 
  there 
  during 
  the 
  summer 
  of 
  1897. 
  

  

  Xot 
  only 
  does 
  a 
  new 
  occurrence 
  of 
  parisite 
  and 
  the 
  peculiar 
  

   habit 
  of 
  the 
  crystals 
  deserve 
  notice, 
  but 
  the 
  chemical 
  compo- 
  

   sition 
  of 
  the 
  mineral 
  has 
  never 
  been 
  determined 
  with 
  certainty, 
  

   and, 
  therefore, 
  analyses 
  have 
  been 
  made 
  for 
  the 
  purpose 
  of 
  

   determining 
  this 
  important 
  character. 
  It 
  is 
  with 
  pleasure 
  that 
  

   we 
  express 
  to 
  Mr. 
  Cahn 
  our 
  thanks 
  for 
  a 
  generous 
  supply 
  of 
  

   the 
  m^aterial 
  from 
  Montana' 
  for 
  analysis. 
  

  

  The 
  parisite 
  crystals 
  from 
  Montana 
  are 
  supposed 
  to 
  have 
  

   come 
  from 
  near 
  Pyrites, 
  Pavalli 
  County, 
  and 
  occur 
  in 
  a 
  fine- 
  

   grained, 
  loosely 
  coherent, 
  white 
  material, 
  which 
  can 
  be 
  readily 
  

   crushed 
  to 
  a 
  powder 
  with 
  the 
  finger 
  nail. 
  The 
  matrix 
  consists 
  

   essentially 
  of 
  silica, 
  alumina, 
  calcium 
  and 
  a 
  little 
  alkali, 
  and 
  

   has 
  the 
  appearance 
  of 
  a 
  decomposed 
  rhyolite 
  or 
  trachyte, 
  but 
  

   its 
  exact 
  nature 
  has 
  not 
  been 
  more 
  definitely 
  determined. 
  

   Through 
  this 
  white 
  material 
  crystals 
  of 
  pyrite 
  and 
  parisite 
  are 
  

   scattered, 
  generally 
  isolated, 
  but 
  at 
  times 
  the 
  parisite 
  has 
  

   grown 
  over 
  and 
  partly 
  or 
  completely 
  surrounded 
  the 
  pyrite 
  

   crystals. 
  The 
  pyrite 
  is 
  crystallized 
  in 
  pyritohedrons 
  modified 
  

   by 
  small 
  faces 
  of 
  the 
  cube 
  and 
  octahedron, 
  and 
  the 
  crystals 
  

   vary 
  in 
  size 
  from 
  microscopic 
  up 
  to 
  3"^™ 
  in 
  diameter. 
  The 
  

   average 
  size 
  of 
  the 
  parisite 
  crystals 
  is 
  about 
  1"°" 
  in 
  diameter 
  

   by 
  10°''^' 
  in 
  length. 
  They 
  are 
  quite 
  numerous, 
  so 
  that 
  from 
  

   four 
  to 
  ten 
  individuals 
  may 
  be 
  seen 
  on 
  a 
  surface 
  of 
  ten 
  square 
  

   centimeters 
  of 
  the 
  matrix. 
  The 
  habit 
  which 
  they 
  generally 
  

   present 
  is 
  that 
  of 
  a 
  horizontally 
  striated 
  hexagonal 
  shaft, 
  made 
  

   up 
  of 
  steep 
  pyramids 
  in 
  oscillatory 
  combination 
  and 
  terminated 
  

   at 
  the 
  ends 
  by 
  distinct, 
  somewhat 
  enlarged 
  pyramids. 
  The 
  

   accompanying 
  figure, 
  which 
  represents 
  a 
  portion 
  of 
  the 
  shaft 
  

   and 
  one 
  termination, 
  gives 
  a 
  fair 
  idea 
  of 
  the 
  development 
  of 
  

   the 
  crystals. 
  The 
  faces 
  which 
  are 
  most 
  prominent 
  in 
  forming 
  

   the 
  shaft 
  are 
  thoscof 
  the 
  pyramid 
  o 
  (20i^l) 
  in 
  oscillatory 
  com- 
  

   bination. 
  Measurements 
  over 
  the 
  reentrant 
  and 
  salient 
  angles 
  

  

  * 
  Brogger. 
  Zeitscbr. 
  Kr., 
  xvi, 
  650, 
  1890. 
  

  

  