﻿Eahins 
  — 
  Analyses 
  of 
  Astrophyllite 
  and 
  Tscheffkinite. 
  35 
  

  

  condition 
  that 
  it 
  was 
  thought 
  a 
  new 
  analysis 
  would 
  be 
  not 
  

   without 
  interest 
  notwithstanding 
  the 
  fact 
  that 
  material 
  from 
  

   the 
  same 
  region 
  had 
  already 
  been 
  analyzed 
  by 
  Konig.* 
  

  

  This 
  astrophyllite 
  occurs 
  in 
  large, 
  brittle, 
  micaceous 
  blades, 
  

   golden 
  to 
  brownish 
  yellow 
  in 
  color, 
  and 
  perfectly 
  free 
  from 
  

   admixed 
  minerals, 
  such 
  as 
  zircon 
  ; 
  the 
  only 
  foreign 
  matter 
  

   being 
  on 
  the 
  ends 
  or 
  sides 
  of 
  the 
  blades 
  which 
  were 
  in 
  contact 
  

   with 
  the 
  containing 
  rock 
  ; 
  so 
  that 
  pure 
  material 
  for 
  analysis 
  

   was 
  readily 
  obtained. 
  In 
  this 
  analysis 
  the 
  zirconia 
  was 
  sep- 
  

   arated 
  by 
  a 
  modification 
  of 
  the 
  hydrogen 
  peroxide 
  method 
  and 
  

   weighed 
  directly, 
  being 
  subsequently 
  identified 
  qualitatively. 
  

   For 
  comparison 
  with 
  this 
  analysis, 
  those 
  made 
  by 
  Konig 
  and 
  

   by 
  Backstromf 
  are 
  added 
  in 
  the 
  table 
  below. 
  Konig's 
  being 
  

   the 
  one 
  previously 
  referred 
  to, 
  of 
  material 
  from 
  the 
  same 
  

   region, 
  and 
  Baekstrom's 
  of 
  the 
  Eikaholmen 
  mineral. 
  

  

  

  Eak 
  

  

  ins. 
  

  

  Konig. 
  

  

  Backstrom. 
  

  

  

  

  Molecular 
  

  

  

  Molecular 
  

  

  

  Molecular 
  

  

  

  Analysis. 
  

  

  ratio. 
  

  

  Analysis. 
  

  

  ratio. 
  

  

  Analysis. 
  

  

  ratio. 
  

  

  Ta 
  2 
  5 
  

  

  0-34 
  

  

  •001 
  

  

  0-80 
  

  

  •002 
  

  

  

  

  Si0 
  2 
  

  

  35-23 
  

  

  •587 
  

  

  34-68 
  

  

  •578 
  

  

  33-02 
  

  

  •550 
  

  

  Ti0 
  2 
  

  

  11-40 
  

  

  •]43 
  

  

  13-58 
  

  

  •170 
  

  

  11-11 
  

  

  •139 
  

  

  Zr0 
  2 
  

  

  1-21 
  

  

  •010 
  

  

  2*20 
  

  

  018 
  

  

  3.65 
  

  

  •030 
  

  

  Fe 
  2 
  3 
  

  

  3-73 
  

  

  •024 
  

  

  6'56 
  

  

  •041 
  

  

  2-53 
  

  

  •016 
  

  

  A1 
  2 
  3 
  

  

  tr. 
  

  

  

  0-70 
  

  

  •007 
  

  

  0-98 
  

  

  •009 
  

  

  FeO 
  

  

  29-02 
  

  

  •403 
  

  

  26-10 
  

  

  •362 
  

  

  21-76 
  

  

  •302 
  

  

  MnO 
  

  

  5*52 
  

  

  •078 
  

  

  3-48 
  

  

  •049 
  

  

  11-96 
  

  

  •169 
  

  

  CaO 
  

  

  0-22 
  

  

  •004 
  

  

  

  

  1-26 
  

  

  •023 
  

  

  MgO 
  

  

  0-13 
  

  

  •003 
  

  

  0-30 
  

  

  •008 
  

  

  0-92 
  

  

  •023 
  

  

  K 
  a 
  O 
  

  

  5-42 
  

  

  •058 
  

  

  5'01 
  

  

  •053 
  

  

  5-78 
  

  

  •062 
  

  

  Na 
  2 
  

  

  3-63 
  

  

  •059 
  

  

  2-54 
  

  

  •041 
  

  

  2-77 
  

  

  •045 
  

  

  H 
  2 
  

  

  4-18 
  

  

  •232 
  

  

  3-54 
  

  

  •197 
  

  

  3-47 
  

  

  •193 
  

  

  

  

  

  CuO 
  -42 
  

  

  •006 
  

  

  F 
  0-97 
  

  

  •051 
  

  

  100-03 
  

  

  99-91 
  

  

  100-18 
  

  

  From 
  a 
  discussion 
  of 
  these 
  analyses 
  of 
  Backstrom 
  and 
  

   Konig, 
  Brogger 
  deduces 
  the 
  general 
  formula 
  : 
  R 
  // 
  4 
  R 
  / 
  4 
  Si(Si0 
  4 
  ) 
  4 
  

   for 
  astrophyllite. 
  It 
  will 
  be 
  seen 
  that 
  my 
  analysis 
  closely 
  

   confirms 
  this 
  formula, 
  agreeing 
  with 
  it 
  better 
  in 
  fact 
  than 
  

   those 
  from 
  which 
  it 
  was 
  derived. 
  Calculating 
  the 
  small 
  

   amount 
  of 
  ferric 
  oxide 
  present 
  in 
  with 
  the 
  B/' 
  group, 
  the 
  

   molecular 
  ratios 
  of 
  my 
  analysis 
  give 
  the 
  following 
  elementary 
  

   proportions 
  : 
  

  

  Si 
  587 
  2389 
  Ti(Zr) 
  153 
  R" 
  536 
  B' 
  2S4 
  H 
  464 
  

   this 
  reduces 
  to 
  : 
  

  

  *Proc. 
  Am. 
  Phil. 
  Soc. 
  Philada., 
  xvi, 
  509, 
  1877. 
  

  

  f 
  Given 
  by 
  Brogger 
  in:— 
  Groth's 
  Zeitschrift, 
  vol. 
  xvi. 
  W. 
  C. 
  Brogger, 
  Die 
  

   Mineralien 
  der 
  Syenitpegmatitgange, 
  etc. 
  

  

  