﻿130 
  

  

  tion 
  of 
  the 
  matrix 
  of 
  the 
  crystal 
  during 
  the 
  time 
  of 
  its 
  formation. 
  In- 
  

   dividuals 
  exhibiting 
  this 
  peculiarity, 
  are 
  not 
  uncommon, 
  and 
  in 
  some 
  

   the 
  number 
  of 
  these 
  so 
  called 
  planes, 
  is 
  still 
  further 
  increased. 
  

  

  Since 
  the 
  publication 
  of 
  the 
  Mineralogy 
  of 
  New-York, 
  I 
  have 
  re- 
  

   ceived 
  sundry 
  specimens 
  of 
  quartz 
  crystals 
  from 
  St. 
  Johnsville, 
  in 
  

   Montgomery 
  county, 
  collected 
  by 
  Mr. 
  Israel 
  Smith, 
  Jr. 
  One 
  of 
  these 
  

   is 
  similar 
  to 
  fig. 
  156, 
  from 
  Middleville, 
  but 
  with 
  the 
  planes, 
  z 
  and 
  z 
  

  

  more 
  extended. 
  Also 
  No. 
  161, 
  of 
  the 
  Mineralogy, 
  and 
  several 
  other 
  

   more 
  common 
  forms, 
  but 
  the 
  crystals 
  are 
  usually 
  quite 
  small. 
  

  

  To 
  the 
  figures 
  of 
  crystals 
  heretofore 
  found 
  in 
  the 
  town 
  of 
  Edwards, 
  

   St. 
  Lawrence 
  county, 
  I 
  have 
  to 
  add 
  the 
  one 
  now 
  introduced, 
  which 
  

   occurs 
  in 
  a 
  group 
  of 
  dodecahedrons, 
  for 
  which 
  that 
  locality 
  is 
  so 
  remark" 
  

  

  able. 
  It 
  is 
  the 
  same 
  form 
  as 
  that 
  from 
  Ulster 
  county, 
  fig. 
  172, 
  of 
  my 
  

   Mineralogy. 
  Some 
  of 
  these 
  crystals 
  have 
  blades 
  of 
  specular 
  iron 
  

  

  