﻿844: 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  quartz 
  is 
  sold 
  for 
  about 
  $3 
  a 
  ton. 
  Tiie 
  percentage 
  of 
  ferric 
  oxid 
  

   in 
  the 
  material 
  influences 
  its 
  commercial 
  value 
  to 
  a 
  large 
  degree, 
  

   as, 
  in 
  the 
  manufacture 
  of 
  white 
  earthenware 
  or 
  porcelain, 
  it 
  ia 
  

   highly 
  essential 
  that 
  the 
  iron 
  percentage 
  in 
  the 
  mixture 
  shall 
  be 
  

   extremely 
  low. 
  For 
  this 
  reason 
  many 
  deposits 
  of 
  feldspar, 
  which 
  

   would 
  othermse 
  be 
  of 
  commercial 
  value, 
  are 
  left 
  untouched. 
  

  

  