﻿352 
  Penfield 
  and 
  Warren 
  — 
  Minerals 
  from 
  Franklin^ 
  N. 
  J. 
  

  

  Lettinjf? 
  R 
  stand 
  for 
  the 
  metals 
  (chiefly 
  mano^anese) 
  the 
  ratio 
  of 
  

   SiO^iEOiH.O 
  is 
  3-03 
  : 
  7*00 
  : 
  1-01, 
  or 
  a 
  close 
  approximation 
  

   to 
  3 
  : 
  7 
  : 
  1, 
  and 
  this 
  leads 
  to 
  the 
  general 
  empirical 
  formula 
  

   HjR.SigOj,. 
  Since 
  water 
  is 
  not 
  expelled 
  from 
  the 
  mineral 
  

   much 
  below 
  a 
  red 
  heat, 
  the 
  hydrogen 
  must 
  exist 
  in 
  the 
  form 
  of 
  

   hydroxyl, 
  and, 
  consequently, 
  the 
  foregoing 
  formula 
  may 
  be 
  

   written 
  E,(R.OH)'2(Si04)3 
  or 
  as 
  a 
  basic 
  orthosilicate, 
  exactly 
  

   equivalent 
  to 
  humite 
  except 
  that 
  no 
  fluorine 
  is 
  present. 
  Con- 
  

   sidering 
  the 
  base 
  wholly 
  as 
  manganese, 
  the 
  following 
  is 
  sug- 
  

   gested 
  as 
  a 
  structural 
  formula 
  of 
  the 
  mineral, 
  which 
  certainly 
  

   appears 
  simple 
  and 
  reasonable, 
  and 
  for 
  comparison 
  the 
  structural 
  

   formula 
  of 
  humite 
  is 
  also 
  given. 
  

  

  Leucophoenicite. 
  Humite. 
  

  

  Mn<g>Si<0-^^"-OH 
  Mg<^>Si<g-^^g-(0«f.F) 
  

   m<C>skC.,. 
  Mg<0>Si<g 
  

  

  Leucophoenicite 
  is 
  therefore 
  a 
  manganese 
  humite, 
  but 
  it 
  

   contains 
  no 
  fluorine 
  isomorphous 
  with 
  the 
  hydroxyl. 
  As 
  

   humite 
  is 
  a 
  magnesium 
  mineral 
  resulting 
  from 
  metamorphism 
  

   due 
  to 
  fumerole 
  or 
  pneumatolitic 
  action, 
  so 
  leucophoenicite 
  

   is 
  a 
  similarly 
  constituted 
  mineral, 
  produced 
  probably 
  by 
  like 
  

   causes 
  at 
  a 
  locality 
  where 
  manganese 
  was 
  abundant. 
  It 
  is 
  

   probable 
  that 
  the 
  crystallization 
  of 
  leucophoenicite 
  is 
  analogous 
  

   to 
  that 
  of 
  the 
  minerals 
  of 
  the 
  humite 
  group, 
  and, 
  since 
  the 
  

   examination 
  of 
  fragments 
  of 
  leucophoenicite 
  in 
  polarized 
  light 
  

   indicated 
  one 
  of 
  the 
  inclined 
  systems 
  (page 
  351), 
  it 
  may 
  be 
  

   inferred 
  that 
  its 
  crystallization 
  is 
  monoclinic, 
  with 
  yS 
  = 
  90, 
  

   analogous 
  to 
  chondrodite 
  and 
  clinohumite, 
  rather 
  than 
  ortho- 
  

   rhombic 
  like 
  humite. 
  Furthermore, 
  the 
  discovery 
  of 
  this 
  

   mineral 
  suggests 
  the 
  possibility 
  of 
  finding 
  a 
  series 
  of 
  manga- 
  

   nese 
  compounds, 
  corresponding 
  to 
  prolectite, 
  chondrodite, 
  

   humite 
  and 
  clinohumite. 
  Attention 
  may 
  also 
  be 
  called 
  to 
  the 
  

   fact 
  that 
  Jannasch 
  and 
  Locke"^' 
  have 
  described 
  a 
  variety 
  of 
  

   humite 
  from 
  Yalais, 
  Switzerland, 
  exactly 
  analogous 
  to 
  leuco- 
  

   phoenicite 
  in 
  that 
  it 
  contains 
  no 
  fluorine. 
  

  

  Before 
  the 
  blowpipe, 
  leucophoenicite 
  fuses 
  quietly 
  at 
  about 
  3 
  

   to 
  a 
  brownish 
  black 
  globule. 
  In 
  the 
  closed 
  tube 
  it 
  yields 
  a 
  

   little 
  water. 
  Reacts 
  for 
  manganese 
  with 
  the 
  fluxes. 
  The 
  

   powdered 
  mineral 
  dissolves 
  very 
  easily 
  in 
  hydrochloric 
  acid, 
  

   and 
  the 
  solution 
  yields 
  gelatinous 
  silica 
  upon 
  evaporation. 
  

  

  *Zeitschr. 
  fur 
  auorganische 
  Cheraie, 
  vii, 
  p, 
  92, 
  189. 
  

  

  