﻿346 
  Pen 
  field 
  and 
  Warren 
  — 
  Minerals 
  from 
  Franhlin^ 
  N. 
  J, 
  

  

  garnet 
  and 
  yellow 
  axinite. 
  The 
  name 
  glaucochroite 
  has 
  been 
  

   given 
  to 
  this 
  species 
  because 
  of 
  its 
  color, 
  from 
  'yXavKo^ 
  = 
  'blue- 
  

   green 
  and 
  xP^'^^ 
  — 
  ^^olor. 
  

  

  3. 
  Nasonite. 
  

  

  This 
  material 
  constitutes 
  the 
  matrix 
  in 
  which 
  the 
  crystals 
  of 
  

   glaucochroite 
  are 
  generally 
  imbedded. 
  It 
  occurs 
  massive, 
  of 
  

   white, 
  color, 
  greasy 
  to 
  adamantine 
  luster, 
  hardness 
  about 
  4, 
  and 
  

   hand 
  specimens 
  usually 
  present 
  a 
  mottled 
  or 
  spotted 
  appearance 
  

   owing 
  to 
  numerous 
  inclusions 
  of 
  yellow 
  axinite 
  and 
  brown 
  

   garnet, 
  which 
  are 
  scattered 
  rather 
  uniformly 
  through 
  the 
  

   massive 
  nasonite. 
  The 
  material 
  that 
  has 
  been 
  examined 
  

   consists 
  of 
  a 
  few 
  specimens 
  collected 
  by 
  S. 
  L. 
  Penfield 
  and 
  

   some 
  sent 
  to 
  us 
  by 
  Mr. 
  W. 
  M. 
  Foote. 
  

  

  Thin 
  sections 
  when 
  examined 
  with 
  the 
  polarizing 
  microscope 
  

   show 
  that 
  the 
  material 
  is 
  crystalline, 
  and 
  that 
  the 
  masses 
  con- 
  

   sist 
  of 
  an 
  intergrowtli 
  of 
  crystal 
  particles, 
  some 
  of 
  which 
  are 
  

   several 
  millimeters 
  in 
  diameter. 
  No 
  pronounced 
  cleavages 
  

   were 
  observed 
  under 
  the 
  microscope, 
  and 
  no 
  crystal 
  boundaries 
  

   were 
  detected 
  which 
  gave 
  any 
  clue 
  to 
  the 
  system 
  of 
  crystalli- 
  

   zation. 
  In 
  convergent 
  polarized 
  light, 
  however, 
  certain 
  sections 
  

   gave 
  a 
  uniaxial 
  interference 
  figure, 
  and, 
  since 
  the 
  massive 
  min- 
  

   eral 
  broke 
  up 
  at 
  times 
  into 
  rude 
  rectangular 
  blocks, 
  it 
  may 
  be 
  

   inferred 
  that 
  the 
  crystallization 
  is 
  tetragonal 
  and 
  that 
  the 
  

   cleavage, 
  which 
  is 
  poor, 
  is 
  prismatic 
  and 
  basal. 
  The 
  birefrin- 
  

   gence 
  is 
  rather 
  strong, 
  and 
  the 
  character 
  of 
  the 
  double 
  refrac- 
  

   tion 
  is 
  positive. 
  

  

  Material 
  for 
  the 
  chemical 
  analysis 
  was 
  obtained 
  by 
  crushing 
  

   a 
  large 
  fragment 
  and 
  picking 
  out 
  the 
  purest 
  material 
  by 
  hand. 
  

   The 
  specific 
  gravity 
  was 
  found 
  to 
  be 
  5*425, 
  and 
  the 
  results 
  of 
  

   the 
  analysis 
  by 
  Warren 
  are 
  as 
  follows 
  : 
  

  

  I 
  II 
  Average 
  Ratio 
  

  

  SiO^ 
  18-4'7 
  18-4'7 
  18-47 
  -308 
  3*00 
  

  

  PbO 
  65-84 
  65-52 
  65-68 
  

  

  ZnO 
  0-84 
  0-80 
  0-82 
  

  

  MnO 
  0-90 
  0-76 
  83 
  

  

  FeO 
  0-10 
  0-10 
  

  

  CaO 
  11-20 
  11-20 
  11-20 
  

  

  CI 
  2-80 
  2-82 
  2-81 
  

  

  H,0 
  0-27 
  0-26 
  0-26^9 
  

  

  294^ 
  

   010 
  I 
  

   Oil 
  )■ 
  -516 
  5-03 
  

  

  001 
  

   200 
  

   079 
  

   029 
  

  

  •108 
  1-05 
  

  

  100-17 
  

   Oxygen 
  equivalent 
  of 
  CI 
  -63 
  

  

  99-54 
  

  

  