﻿Larsen 
  — 
  Eakleite, 
  a 
  New 
  Mineral 
  from 
  California. 
  465 
  

  

  The 
  optical 
  properties 
  of 
  eakleite 
  are 
  characteristic. 
  It 
  is 
  

   pale 
  pink 
  with 
  vitreous 
  to 
  silky 
  luster. 
  Under 
  the 
  microscope 
  

   libers 
  give 
  parallel 
  extinction 
  and 
  are 
  seen 
  to 
  be 
  elongated 
  

   parallel 
  to 
  Z. 
  It 
  is 
  optically 
  positive 
  and 
  the 
  axial 
  angle 
  is 
  

   very 
  small. 
  

  

  The 
  indices 
  of 
  refraction 
  as 
  measured 
  in 
  sodium 
  light 
  by 
  the 
  

   immersion 
  method 
  are 
  : 
  

  

  a 
  = 
  1-583 
  ± 
  O'OOl. 
  

   (3 
  = 
  1-583 
  ± 
  0-001. 
  

   y 
  = 
  1-593 
  ± 
  0-001. 
  

  

  Chemical 
  analyses. 
  — 
  Two 
  chemical 
  analyses 
  of 
  a 
  sample 
  of 
  

   the 
  mineral, 
  which 
  a 
  microscopic 
  examination 
  showed 
  to 
  be 
  

   free 
  from 
  impurities 
  and 
  homogeneous, 
  were 
  kindly 
  made 
  for 
  

   the 
  author 
  by 
  Professor 
  Eakle, 
  and 
  are 
  given 
  in 
  columns 
  1 
  and 
  

   2 
  of 
  the 
  table. 
  Column 
  3 
  gives 
  the 
  average 
  of 
  the 
  two 
  

   analyses, 
  column 
  4 
  gives 
  the 
  molecular 
  ratios, 
  and 
  column 
  5 
  

   the 
  theoretical 
  composition 
  of 
  a 
  mineral 
  with 
  the 
  formula 
  

   5Ca0.5Si0 
  2 
  .H 
  2 
  0. 
  

  

  Analyses 
  and 
  ratios 
  of 
  Eakleite. 
  

  

  

  1 
  

  

  2 
  

  

  3 
  

  

  4 
  

  

  

  5 
  

  

  Si0 
  2 
  

  

  50-43 
  

  

  49-90 
  

  

  50-17 
  

  

  832 
  

  

  5 
  X 
  166 
  

  

  50-16 
  

  

  Fe„0 
  3 
  

  

  0-98 
  

  

  1-11 
  

  

  1-04 
  

  

  6 
  

  

  

  

  CaO 
  

  

  45-51 
  

  

  45-39 
  

  

  45-45 
  

  

  812 
  

  

  5 
  X 
  168 
  

  

  46-82 
  

  

  MgO 
  

  

  tr. 
  

  

  tr. 
  

  

  tr. 
  

  

  

  

  

  Na 
  2 
  & 
  K 
  2 
  

  

  none 
  

  

  none 
  

  

  none 
  

  

  

  

  

  H 
  2 
  

  

  3-25 
  

  

  3-11 
  

  

  3-18 
  

  

  177 
  

  

  1 
  X 
  177 
  

  

  3-02 
  

  

  

  100-17 
  

  

  99-5 
  1 
  

  

  

  

  

  100-00 
  

  

  The 
  relation 
  of 
  eakleite 
  to 
  other 
  minerals 
  is 
  not 
  clear, 
  but 
  it 
  

   may 
  be 
  a 
  calcium 
  pectolite, 
  as 
  some 
  analyses 
  of 
  pectolite 
  show 
  

   an 
  excess 
  of 
  water 
  over 
  that 
  commonly 
  assigned 
  to 
  the 
  species. 
  

   Its 
  fibrous 
  structure 
  and 
  general 
  appearance 
  are 
  those 
  of 
  

   pectolite. 
  

  

  