﻿636 
  R. 
  C. 
  Wells 
  — 
  New 
  Occurrence 
  of 
  Cuprodescloizite. 
  

  

  Art. 
  LV. 
  — 
  A 
  New 
  Occurrence 
  of 
  Guprodescloizite 
  /* 
  by 
  

   Poger 
  C. 
  Wells. 
  

  

  A 
  mineral 
  recently 
  received 
  for 
  inspection 
  by 
  the 
  United 
  

   States 
  Geological 
  Survey 
  was 
  provisionally 
  identified 
  as 
  cupro- 
  

   descloizite. 
  It 
  was 
  collected 
  by 
  Philip 
  D. 
  Wilson 
  of 
  Bisbee, 
  

   Arizona, 
  who 
  stated 
  that 
  it 
  is 
  found 
  in 
  some 
  quantity 
  in 
  the 
  

   Shattuck 
  Arizona 
  mine 
  in 
  Bisbee, 
  and 
  that 
  it 
  is 
  the 
  first 
  occur- 
  

   rence 
  of 
  a 
  vanadium 
  mineral 
  noted 
  in 
  that 
  district. 
  On 
  

   account 
  of 
  its 
  unusual 
  form 
  and 
  composition, 
  an 
  analysis 
  

   seemed 
  advisable 
  and 
  for 
  this 
  purpose 
  Mr. 
  Wilson 
  generously 
  

   placed 
  a 
  large 
  amount 
  of 
  material 
  at 
  the 
  disposal 
  of 
  the 
  Chem- 
  

   ical 
  Laboratory 
  of 
  the 
  Survey. 
  

  

  General 
  description. 
  — 
  The 
  mineral 
  occurs 
  in 
  the 
  form 
  of 
  

   stalactites. 
  The 
  smaller 
  aggregates 
  radiate 
  from 
  a 
  narrow 
  

   base 
  and 
  end 
  in 
  rounded 
  clusters 
  l-8 
  mm 
  in 
  diameter. 
  The 
  

   larger 
  growths 
  occur 
  in 
  reniform 
  masses 
  several 
  centimeters 
  in 
  

   diameter. 
  The 
  latter 
  are 
  coated 
  with 
  a 
  red 
  powder, 
  but 
  the 
  

   smaller 
  aggregates 
  have 
  an 
  olive 
  hue. 
  The 
  fractured 
  surface 
  

   of 
  all 
  varieties 
  possesses 
  a 
  dark 
  brown 
  luster 
  and 
  shows 
  a 
  

   radiating 
  structure. 
  The 
  streak 
  is 
  " 
  dark 
  olive-buff," 
  Plate 
  

   XL 
  of 
  Pidgeway's 
  color 
  standards,-)* 
  and 
  the 
  powder 
  somewhat 
  

   darker. 
  

  

  Dr. 
  W. 
  T. 
  Schaller 
  has 
  kindly 
  made 
  the 
  following 
  observa- 
  

   tions 
  upon 
  the 
  optical 
  properties 
  : 
  " 
  The 
  broad 
  fibers 
  have 
  

   parallel 
  extinction. 
  The 
  elongation 
  is 
  X. 
  The 
  pleochroism 
  is 
  

   marked 
  : 
  parallel 
  elongation, 
  yellow 
  ; 
  normal 
  thereto, 
  brown. 
  

   Absorption, 
  brown 
  > 
  yellow. 
  Refractive 
  indices 
  high, 
  greater 
  

   than 
  1'74. 
  Birefringence 
  strong, 
  estimated 
  0*03 
  to 
  0*04. 
  Indi- 
  

   cations 
  of 
  biaxiality 
  were 
  seen, 
  but 
  the 
  individual 
  crystal 
  units 
  

   were 
  too 
  small 
  to 
  permit 
  of 
  any 
  definite 
  results 
  being 
  obtained." 
  

  

  Chemical 
  Investigation. 
  — 
  The 
  mineral 
  was 
  almost 
  com- 
  

   pletely 
  soluble 
  in 
  dilute 
  nitric 
  acid. 
  The 
  small 
  insoluble 
  por- 
  

   tion 
  was 
  found 
  to 
  be 
  chiefly 
  lead 
  chromate, 
  soluble 
  in 
  more 
  

   concentrated 
  nitric 
  acid 
  after 
  decantation 
  of 
  the 
  main 
  solution. 
  

   Hydrochloric 
  acid 
  transposed 
  the 
  mineral 
  into 
  lead 
  chloride, 
  

   copper 
  chloride 
  and 
  vanadic 
  acid. 
  Sulphuric 
  acid 
  decomposed 
  

   it 
  with 
  precipitation 
  of 
  lead 
  sulphate. 
  Lead 
  was 
  determined 
  

   as 
  sulphate, 
  either 
  after 
  separation 
  as 
  sulphide, 
  or 
  after 
  direct 
  

   precipitation 
  as 
  sulphate. 
  Copper" 
  was 
  determined 
  as 
  metal 
  

   after 
  separation 
  as 
  sulphide 
  and 
  electrolysis. 
  Lead 
  and 
  copper 
  

   having 
  been 
  removed 
  by 
  a 
  rapid 
  stream 
  of 
  hydrogen-sulphide, 
  

   arsenic 
  was 
  separated 
  as 
  sulphide 
  after 
  one 
  to 
  three 
  days 
  

  

  * 
  Published 
  with 
  the 
  permission 
  of 
  the 
  Director 
  of 
  the 
  United 
  States 
  Geo- 
  

   logical 
  Survey. 
  

  

  f 
  Robert 
  Ridgeway, 
  "Color 
  Standards 
  and 
  Nomenclature." 
  Washington, 
  

   D. 
  C, 
  1912. 
  

  

  