﻿8. 
  L. 
  Pen 
  field 
  — 
  Graftonite^ 
  a 
  new 
  Mineral. 
  

  

  21 
  

  

  3j. 
  

  

  Fortunately 
  for 
  the 
  solution 
  of 
  the 
  problem 
  in 
  hand, 
  among 
  

   several 
  pounds 
  of 
  material 
  sent 
  by 
  Mr. 
  English, 
  a 
  single 
  frag- 
  

   ment, 
  about 
  as 
  large 
  as 
  the 
  end 
  of 
  one's 
  finger, 
  was 
  found, 
  

   which 
  showed 
  only 
  a 
  very 
  little 
  of 
  the 
  dark, 
  decomposed 
  

   material. 
  It 
  was 
  undoubtedly 
  the 
  central 
  portion 
  or 
  core 
  of 
  a 
  

   crystal, 
  the 
  outer 
  portion 
  of 
  which 
  had 
  been 
  oxidized, 
  leaving 
  

   within 
  a 
  core 
  of 
  fresh 
  unaltered 
  material. 
  Upon 
  careful 
  

   examination 
  this 
  fresh 
  portion 
  was 
  found 
  to 
  consist 
  of 
  two 
  

   minerals 
  in 
  alternating 
  layers, 
  and 
  fig. 
  1, 
  which 
  represents 
  the 
  

   appearance 
  of 
  a 
  thin 
  section 
  prepared 
  at 
  approximately 
  right 
  

   angles 
  to 
  the 
  lamination, 
  will 
  give 
  an 
  idea 
  of 
  the 
  arrangement 
  

   and 
  relative 
  proportions 
  of 
  the 
  two 
  minerals. 
  The 
  white 
  por- 
  

   tions, 
  g, 
  represent 
  the 
  new 
  mineral, 
  graftonite, 
  which 
  consti- 
  

   tutes 
  about 
  two-thirds 
  to 
  three-quarters 
  of 
  the 
  

   total 
  material. 
  This 
  in 
  the 
  fragment 
  possessed 
  1 
  

  

  a 
  delicate 
  salmon 
  color, 
  but 
  appeared 
  almost 
  

   colorless 
  in 
  thin 
  section. 
  The 
  other 
  mineral 
  t, 
  

   which 
  in 
  the 
  figure 
  is 
  represented 
  by 
  the 
  

   stippled 
  portions, 
  was 
  found 
  to 
  be 
  triphylite. 
  

   The 
  latter 
  possessed 
  a 
  pale 
  green 
  color 
  as 
  seen 
  

   in 
  the 
  fragment, 
  but 
  appeared 
  almost 
  colorless 
  

   in 
  thin 
  section. 
  The 
  exterior 
  of 
  this 
  fragment 
  

   of 
  fresh 
  material 
  showed 
  in 
  places 
  a 
  darken- 
  

   ing, 
  due 
  to 
  the 
  oxidation 
  of 
  the 
  iron 
  and 
  

   manganese, 
  and 
  the 
  thin 
  section 
  showed, 
  as 
  

   represented 
  by 
  fig. 
  1, 
  that 
  the 
  oxidation 
  is 
  con- 
  

   fined 
  wholly 
  to 
  the 
  triphylite 
  lamellae, 
  the 
  new 
  

   mineral 
  being 
  evidently 
  a 
  more 
  stable 
  material. 
  

   On 
  breaking 
  up 
  the 
  fragment 
  it 
  was 
  found 
  

   that 
  the 
  lamellae 
  separated 
  quite 
  readily, 
  and 
  it 
  

   was 
  possible 
  to 
  obtain 
  the 
  two 
  minerals 
  practi- 
  

   cally 
  pure, 
  by 
  careful 
  working, 
  splitting 
  off 
  

   lamellae 
  at 
  times 
  almost 
  as 
  thin 
  as 
  a 
  sheet 
  of 
  

   paper, 
  and 
  examining 
  each 
  particle 
  with 
  a 
  lens. 
  

   Thus, 
  discarding 
  everything 
  which 
  seemed 
  at 
  

   all 
  questionable 
  and 
  using 
  all 
  of 
  the 
  available 
  material, 
  0*546 
  

   grams 
  of 
  the 
  new 
  mineral 
  and 
  0*166 
  grams 
  of 
  the 
  triphylite 
  

   were 
  secured. 
  The 
  specific 
  gravity 
  of 
  the 
  graftonite 
  was 
  

   found 
  to 
  be 
  3*672. 
  The 
  hardness 
  is 
  5 
  and 
  the 
  luster 
  is 
  vitreous 
  

   to 
  resinous. 
  In 
  appearance 
  it 
  resembles 
  very 
  closely 
  the 
  

   salmon-colored 
  varieties 
  of 
  lithiophilite. 
  The 
  associated 
  tri- 
  

   phylite 
  was 
  found 
  to 
  have 
  a 
  specific 
  gravity 
  of 
  3*58. 
  

  

  Making 
  complete 
  analyses 
  of 
  the 
  two 
  minerals 
  on 
  the 
  small 
  

   quantities 
  of 
  available 
  material 
  proved 
  to 
  be 
  a 
  somewhat 
  inter- 
  

   esting 
  problem 
  in 
  analytical 
  chemistry, 
  and 
  a 
  brief 
  outline 
  of 
  

   the 
  method 
  employed 
  is 
  as 
  follows 
  : 
  It 
  was 
  first 
  proved 
  by 
  

   qualitative 
  tests 
  that 
  the 
  iron 
  was 
  wholly 
  ferrous. 
  All 
  of 
  the 
  

  

  