﻿W. 
  T. 
  Schaller 
  — 
  Identity 
  of 
  Ilamlinite 
  with 
  Goyazite. 
  163 
  

  

  Art. 
  XVI. 
  — 
  On 
  the 
  Identity 
  of 
  Ilamlinite 
  with 
  Goyazite 
  ; 
  

   by 
  Waldemar 
  T. 
  Schaller. 
  

  

  Farrington* 
  has 
  recently 
  stated 
  that 
  the 
  present 
  evidence 
  

   hardly 
  seems 
  sufficient 
  for 
  regarding 
  the 
  two 
  minerals, 
  goya- 
  

   zite 
  and 
  hamlinite, 
  as 
  identical. 
  Damour's 
  original 
  formula 
  

   for 
  goyazite 
  would 
  then 
  have 
  to 
  be 
  accepted 
  even 
  though 
  it 
  

   " 
  evidently 
  needs 
  confirmation 
  " 
  as 
  Farrington 
  states. 
  

  

  The 
  resemblance 
  of 
  goyazite 
  and 
  hamlinite 
  in 
  their 
  physical 
  

   and 
  optical 
  properties 
  is 
  great 
  enough 
  to 
  warrant 
  the 
  sugges- 
  

   tion 
  that 
  their 
  chemical 
  composition 
  is 
  of 
  the 
  same 
  type 
  of 
  

   formula, 
  and 
  since 
  Damour's 
  calcium 
  has 
  been 
  shown 
  to 
  be 
  

   essentially 
  strontium, 
  the 
  two 
  minerals 
  have 
  the 
  same 
  qualita- 
  

   tive 
  composition, 
  both 
  being 
  hydrous 
  phosphates 
  of 
  aluminium 
  

   and 
  strontium. 
  If 
  their 
  formulas 
  are 
  of 
  the 
  same 
  type, 
  it 
  is 
  

   most 
  reasonable 
  to 
  consider 
  them 
  identical 
  — 
  until 
  they 
  are 
  

   proven 
  to 
  be 
  different. 
  

  

  The 
  table 
  published*} 
  - 
  earlier 
  by 
  the 
  writer 
  showed 
  the 
  proba- 
  

   ble 
  identity 
  of 
  the 
  two 
  minerals 
  goyazite 
  and 
  hamlinite. 
  In 
  

   order 
  to 
  emphasize 
  the 
  possible 
  distinction 
  between 
  these 
  two 
  

   minerals, 
  Farrington 
  has 
  published 
  a 
  table 
  of 
  differences 
  between 
  

   them 
  ; 
  there 
  are, 
  however, 
  three 
  errors 
  in 
  the 
  six 
  items 
  listed 
  

   in 
  this 
  table. 
  

  

  The 
  percentage 
  of 
  P 
  2 
  5 
  for 
  hamlinite 
  is 
  wrongly 
  given 
  as 
  

   20*92 
  per 
  cent. 
  It 
  should 
  be 
  28'92 
  per 
  cent. 
  The 
  suggestion 
  

   was 
  earlier 
  made 
  that 
  the 
  separation 
  of 
  P 
  2 
  5 
  from 
  A1 
  2 
  3 
  was 
  

   probably 
  not 
  accurate 
  in 
  Damour's 
  analysis 
  of 
  goyazite, 
  so 
  

   that 
  the 
  comparison 
  between 
  the 
  sums 
  of 
  P 
  2 
  O 
  s 
  and 
  A1 
  2 
  3 
  for 
  

   the 
  two 
  minerals 
  (65*53 
  and 
  62*87), 
  is 
  probably 
  the 
  most 
  valid 
  

   comparison 
  of 
  the 
  analytical 
  figures. 
  

  

  Goyazite 
  is 
  stated 
  by 
  Farrington 
  in 
  his 
  table 
  to 
  be 
  " 
  Infusi- 
  

   ble." 
  The 
  original 
  description 
  states;}; 
  : 
  "Ala 
  flamrae 
  du 
  chalu- 
  

   meau, 
  il 
  fond 
  difficilement 
  sur 
  les 
  bords 
  des 
  plus 
  minces 
  frag- 
  

   ments." 
  Damour's 
  statement 
  regarding 
  goyazite, 
  " 
  il 
  fond 
  

   difficilement," 
  and 
  Penfield's 
  statement 
  for 
  hamlinite, 
  " 
  fuses 
  

   about 
  4," 
  show 
  a 
  resemblance, 
  not 
  a 
  difference. 
  

  

  The 
  table 
  of 
  Farrington 
  states 
  further 
  that 
  hamlinite 
  is 
  

   " 
  slowly 
  soluble 
  in 
  acids." 
  This 
  statement, 
  quoted 
  in 
  Dana's 
  

   System 
  of 
  Mineralogy, 
  on 
  page 
  762, 
  must 
  be 
  somewhat 
  modi- 
  

  

  * 
  Farrington, 
  O. 
  C, 
  Studies 
  of 
  Brazilian 
  favas, 
  this 
  Journal 
  (4), 
  xli, 
  p. 
  

  

  358, 
  1916. 
  

  

  f 
  Schaller, 
  W. 
  T., 
  The 
  alunite-beudantite 
  group, 
  this 
  Journal 
  (4), 
  xxxii, 
  

  

  359, 
  1911. 
  Also, 
  U. 
  S. 
  Geol. 
  Survey 
  Bull. 
  509, 
  p. 
  70, 
  1912. 
  

  

  X 
  Damour, 
  A. 
  , 
  Note 
  sur 
  un 
  nouveau 
  phosphate 
  d'alumine 
  et 
  de 
  chaux, 
  des 
  

   terrains 
  diamantiferes, 
  Bull. 
  Soc. 
  Min., 
  France, 
  vol. 
  xvii, 
  204, 
  1885. 
  

  

  