﻿96 
  E. 
  V. 
  Shannon 
  — 
  New 
  Description 
  of 
  Amesite. 
  

  

  Aet. 
  VI. 
  — 
  A 
  New 
  Description 
  of 
  Amesite; 
  by 
  Earl 
  V. 
  

  

  Shannon. 
  1 
  

  

  The 
  name 
  amesite 
  was 
  given 
  by 
  C. 
  U. 
  Shepard 
  to 
  a 
  

   pale 
  green 
  chlorite 
  occurring 
  in 
  intimate 
  association 
  with 
  

   diaspore 
  at 
  the 
  old 
  emery 
  mine 
  in 
  Chester, 
  Mass. 
  The 
  

   mineral 
  which 
  was 
  analyzed 
  by 
  Pisani 
  2 
  is 
  described 
  as 
  

   in 
  hexagonal 
  plates 
  ; 
  foliated, 
  resembling 
  the 
  green 
  talc 
  

   from 
  the 
  Tyrol. 
  Hardness 
  2-5-3-0 
  ; 
  specific 
  gravity 
  2-71 
  ; 
  

   sensibly 
  uniaxial, 
  optically 
  positive; 
  color 
  pale 
  apple- 
  

   green; 
  luster 
  pearly 
  on 
  the 
  cleavage 
  face. 
  Composition 
  

   approximating 
  to 
  H 
  4 
  (Mg,Fe) 
  2 
  Al 
  2 
  Si0 
  9 
  . 
  

  

  Tschermak 
  3 
  later 
  took 
  amesite 
  as 
  representing 
  a 
  fun- 
  

   damental 
  end 
  member 
  and 
  explained 
  the 
  constitution 
  of 
  

   the 
  orthochlorites 
  by 
  assuming 
  them 
  to 
  be 
  isomorphous 
  

   mixtures 
  of 
  the 
  amesite 
  molecule 
  and 
  the 
  serpentine 
  

   molecule. 
  Considerable 
  interest 
  thus 
  attaches 
  to 
  the 
  

   mineral 
  which 
  has 
  been 
  found 
  only 
  at 
  this 
  exhausted 
  

   locality. 
  Since 
  no 
  other 
  analysis 
  of 
  amesite 
  than 
  that 
  of 
  

   Pisani 
  appears 
  to 
  have 
  been 
  made 
  and 
  in 
  order 
  to 
  deter- 
  

   mine 
  the 
  refractive 
  indices 
  on 
  analyzed 
  material, 
  the 
  

   mineral 
  has 
  recently 
  been 
  reanalyzed, 
  abundant 
  material 
  

   for 
  investigation 
  being 
  supplied 
  by 
  a 
  specimen 
  in 
  the 
  

   museum 
  collection. 
  This 
  specimen 
  is 
  labeled 
  " 
  amesite 
  

   and 
  diaspore, 
  Chester, 
  Mass." 
  in 
  the 
  handwriting 
  of 
  

   C. 
  U. 
  Shepard 
  and 
  the 
  label 
  bears 
  also 
  the 
  words 
  "Coll. 
  

   by 
  E. 
  Messia," 
  by 
  which 
  is 
  probably 
  meant 
  Macia, 
  a 
  

   French 
  Canadian, 
  for 
  many 
  years 
  foreman 
  at 
  the 
  emery 
  

   mine 
  and 
  an 
  ardent 
  collector 
  of 
  minerals. 
  The 
  specimen 
  

   consisted 
  of 
  a 
  large 
  flat 
  mass 
  of 
  diaspore 
  showing 
  pale 
  

   grayish-pink 
  cleavages 
  several 
  inches 
  broad 
  where 
  

   broken 
  and 
  containing 
  small 
  cavities 
  filled 
  with 
  interlac- 
  

   ing 
  needle-like 
  crystals 
  of 
  diaspore. 
  One 
  side 
  of 
  the 
  

   specimen 
  is 
  completely 
  coated 
  with 
  a 
  layer 
  of 
  flat 
  amesite 
  

   crystals 
  of 
  a 
  pale 
  green 
  color 
  somewhat 
  iron 
  stained. 
  

   Scattered 
  through 
  the 
  mass 
  of 
  the 
  diaspore 
  there 
  are 
  

   variously 
  oriented 
  crystals 
  of 
  amesite, 
  large 
  octahedrons 
  

   of 
  magnetite 
  and 
  crystals 
  of 
  dark 
  red 
  to 
  black 
  rutile. 
  

   The 
  amesite 
  occurs 
  in 
  tabular 
  hexagonal 
  crystals 
  with 
  

   dull 
  prismatic 
  faces. 
  They 
  reach 
  an 
  extreme 
  diameter 
  

  

  1 
  Published 
  by 
  permission 
  of 
  the 
  Secretary 
  of 
  the 
  Smithsonian 
  Insti- 
  

   tution. 
  

  

  2 
  Pisani, 
  C. 
  E., 
  83, 
  166, 
  1876. 
  

  

  3 
  Theil, 
  Ber. 
  Ak. 
  Wein, 
  99 
  (1), 
  174-267, 
  1890. 
  

  

  