﻿Larsen 
  and 
  Hunt 
  — 
  Vanadiferous 
  JEgirites. 
  291 
  

  

  an 
  end 
  termination. 
  Crystals 
  of 
  this 
  habit 
  were 
  generally 
  

   noted 
  in 
  compact 
  columnar 
  intergrowths. 
  The 
  second 
  type, 
  

   which 
  is 
  shown 
  in 
  figure 
  2, 
  is 
  decidedly 
  needle-like 
  in 
  character 
  

   with 
  broken 
  ends. 
  It 
  is 
  characteristic 
  of 
  the 
  crystals 
  in 
  the 
  

   spherulitic 
  aggregates. 
  In 
  both 
  types 
  the 
  unit 
  prism 
  is 
  the 
  

   predominant 
  form 
  in 
  the 
  vertical 
  zone 
  which 
  emphasizes 
  the 
  

   quadratic 
  cross 
  section. 
  The 
  clino- 
  and 
  ortho-prisms 
  as 
  well 
  as 
  

   the 
  corresponding 
  pinacoids 
  are 
  extremely 
  small. 
  The 
  reflec- 
  

  

  FlG. 
  1 
  

  

  Fig. 
  2. 
  

  

  — 
  - 
  

  

  --■ 
  

  

  - 
  

  

  -J* 
  1 
  

  

  ~T~TT-T" 
  

  

  ^F 
  

  

  77? 
  

  

  f 
  

  

  V 
  

  

  41 
  

  

  b 
  

   z 
  

  

  tions 
  obtained 
  were, 
  for 
  the 
  most 
  part, 
  far 
  from 
  ideal, 
  the 
  larger 
  

   prism 
  faces 
  showing 
  multiple 
  images 
  as 
  a 
  result 
  of 
  vertical 
  

   striations, 
  while 
  to 
  obtain 
  a 
  sharp 
  reflection 
  from 
  the 
  ortho- 
  

   dome 
  a 
  small 
  piece 
  of 
  cover 
  glass 
  was 
  cemented 
  to 
  the 
  rather 
  

   large 
  but 
  non-reflecting 
  surface. 
  In 
  spite 
  of 
  these 
  physical 
  

   imperfections 
  the 
  close 
  agreement 
  between 
  the 
  average 
  of 
  a 
  

   large 
  number 
  of 
  observed 
  readings 
  with 
  the 
  corresponding 
  

   values 
  reported 
  for 
  segirite 
  by 
  Brogger* 
  leaves 
  no 
  doubt 
  what- 
  

   ever 
  as 
  to 
  the 
  identity 
  of 
  the 
  forms 
  given 
  in 
  Table 
  I. 
  In 
  this 
  

   table 
  under 
  " 
  Observed 
  " 
  are 
  given 
  the 
  angles 
  measured 
  by 
  

   Hunt 
  on 
  the 
  vanadiferous 
  segirite 
  from 
  Montana 
  and 
  in 
  the 
  

   following 
  column 
  are 
  given 
  the 
  corresponding 
  angles 
  measured 
  

   by 
  Brogger 
  on 
  aegirite 
  from 
  Norway. 
  

  

  Of 
  the 
  forms 
  listed 
  below 
  the 
  only 
  one 
  which 
  has 
  not 
  pre- 
  

   viously 
  been 
  reported 
  on 
  segirite 
  is 
  the 
  clinoprism 
  i 
  [130]. 
  

   It 
  was 
  found 
  only 
  on 
  those 
  crystals 
  showing 
  the 
  short 
  prismatic 
  

   development 
  (fig. 
  1). 
  While 
  apparently 
  new 
  for 
  gegirite, 
  it 
  has 
  

  

  * 
  Brogger, 
  W. 
  C, 
  Zeitschr. 
  f. 
  Kryst., 
  vol. 
  xvi, 
  p. 
  319, 
  1890. 
  

  

  