﻿496 
  Luedeking 
  and 
  Wheeler 
  — 
  Notes 
  on 
  a 
  Missouri 
  Barite. 
  

  

  white 
  to 
  yellowish 
  thin 
  bands 
  in 
  an 
  otherwise 
  normal 
  colorless 
  

   barite, 
  and 
  analysis 
  shows 
  that 
  these 
  bands 
  consist 
  of 
  a 
  mixture 
  

   of 
  the 
  sulphates 
  of 
  barium 
  and 
  strontium 
  with 
  slight 
  amounts 
  

   of 
  calcium 
  and 
  ammonium. 
  

  

  Two 
  distinct 
  types 
  of 
  the 
  banded 
  crystals 
  occur, 
  of 
  which 
  

   one 
  type 
  (A, 
  B) 
  is 
  found 
  near 
  Smith 
  ton, 
  while 
  the 
  other 
  type 
  (C, 
  

   D, 
  E) 
  is 
  found 
  at 
  Sedalia, 
  both 
  localities 
  being 
  within 
  seven 
  

   miles 
  of 
  each 
  other 
  in 
  Pettis 
  Co., 
  Mo. 
  They 
  occur 
  in 
  clay 
  

   associated 
  with 
  galena 
  in 
  the 
  lead-bearing 
  magnesia 
  limestone 
  

   series 
  of 
  Missouri, 
  which 
  latter 
  in 
  that 
  locality 
  usually 
  has 
  

   barite 
  very 
  abundantly 
  associated 
  with 
  the 
  lead 
  ores. 
  

  

  The 
  crystal, 
  A, 
  consists 
  of 
  the 
  right 
  rhombic 
  prism, 
  bev- 
  

   eled 
  by 
  the 
  right 
  rhombic 
  jryramid 
  and 
  truncated 
  by 
  the 
  basal 
  

   pinacoid 
  ; 
  another 
  crystal, 
  B, 
  is 
  in 
  addition 
  modified 
  by 
  the 
  

   macro- 
  and 
  brachydomes, 
  which, 
  like 
  the 
  pyramid, 
  have 
  very 
  

   low 
  values 
  for 
  the 
  coefficient 
  of 
  the 
  vertical 
  axis. 
  All 
  the 
  

   faces 
  of 
  the 
  modifications 
  of 
  the 
  A 
  and 
  B 
  forms 
  of 
  crystals, 
  

   except 
  the 
  basal 
  pinacoid, 
  are 
  coated 
  with 
  an 
  opaque 
  white 
  

   variety 
  of 
  barite, 
  next 
  to 
  which 
  is 
  a 
  colorless 
  band 
  followed 
  by 
  

   a 
  narrow 
  white 
  band, 
  the 
  body 
  of 
  the 
  crystal 
  being 
  clear 
  and 
  

   colorless. 
  The 
  inner 
  white 
  band 
  is 
  from 
  0*5 
  to 
  i-0 
  mm 
  wide 
  

  

  