﻿Report 
  of 
  the 
  State 
  Geologist. 
  

  

  701 
  

  

  Sterling 
  variety 
  is 
  most 
  closely 
  related 
  to 
  the 
  chlorites, 
  though 
  in 
  

   some 
  respects 
  resembling 
  the 
  rather 
  obscure 
  hydrous 
  silicates, 
  

   hisingerite, 
  gillingite, 
  jolly 
  ite, 
  etc. 
  It 
  is 
  important 
  to 
  note 
  that 
  

   Roth* 
  describes 
  these 
  as 
  minerals 
  which 
  are 
  formed 
  where 
  pyrite 
  

   decomposes 
  in 
  the 
  presence 
  of 
  silicates. 
  This 
  fact 
  of 
  a 
  general 
  

   nature 
  lends 
  additional 
  strength 
  to 
  the 
  theory 
  here 
  advanced. 
  

  

  

  i. 
  

  

  n. 
  

  

  m. 
  

  

  Si 
  2 
  : 
  

  

  29.70 
  

  

  17.03 
  

  

  27.15 
  

  

  10.66 
  

  

  1.68 
  

  

  0.56 
  

  

  0.10 
  

  

  11.79 
  

  

  46.90 
  

   35.73 
  

   2.48 
  

   0.83 
  

   0.45 
  

   0.48 
  

   6.41 
  

   5.00 
  

  

  46.70 
  

  

  A,0, 
  

  

  31.01 
  

  

  Fe 
  

  

  3.69 
  

  

  MffO 
  

  

  0.50 
  

  

  Ca 
  

  

  Trace. 
  

  

  Na, 
  

  

  Trace. 
  

  

  K 
  2 
  

  

  11.68 
  

  

  H 
  2 
  

  

  5.30 
  

  

  

  

  

  98.63 
  

  

  98.88 
  

  

  98.88 
  

  

  I. 
  " 
  Serpentine," 
  altered 
  granite, 
  Old 
  Sterling 
  mine. 
  

  

  II. 
  " 
  Serpentine," 
  presumably 
  altered 
  granite, 
  Caledonia 
  mine. 
  

  

  III. 
  " 
  Dysyntribite." 
  (Smith 
  and 
  Brush.) 
  

  

  In 
  the 
  writer's 
  analyses, 
  I 
  and 
  II, 
  though 
  all 
  of 
  the 
  iron 
  is 
  

   calculated 
  as 
  ferrous 
  oxide, 
  a 
  minor 
  portion 
  of 
  it 
  is 
  present 
  in 
  the 
  

   form 
  of 
  ferric 
  oxide. 
  There 
  is 
  sulphuric 
  acid 
  present 
  also 
  in 
  both 
  

   samples, 
  as 
  shown 
  by 
  qualitative 
  tests. 
  These 
  two 
  factors, 
  if 
  

   reckoned 
  in, 
  would 
  materially 
  increase 
  the 
  totals 
  shown 
  above. 
  

   Analysis 
  III, 
  of 
  the 
  Dysyntribite 
  of 
  Shepard, 
  is 
  introduced 
  for 
  

   comparison. 
  

  

  The 
  chemistry 
  of 
  the 
  process 
  of 
  ore 
  formation 
  is 
  quite 
  simple, 
  

   involving 
  only 
  familiar 
  reactions, 
  well 
  known 
  both 
  in 
  laboratory 
  

   and 
  field. 
  The 
  resulting 
  ore 
  would 
  be 
  limonite, 
  and 
  siderite, 
  

   which 
  would 
  be 
  changed 
  to 
  limonite 
  by 
  oxidation 
  as 
  continued 
  

  

  * 
  J. 
  Roth, 
  Allgemeine 
  und 
  Chemiache 
  Gteologie, 
  Bd. 
  I, 
  p. 
  238. 
  

  

  