﻿152 
  

  

  Cleavage 
  perfect, 
  very 
  distinct 
  in 
  the 
  direction 
  of 
  the 
  short 
  diagonal 
  ; 
  

   indistinct 
  approaching 
  distinctness 
  in 
  the 
  direction 
  of 
  the 
  long 
  diago- 
  

   nal 
  ; 
  hemiprismatic 
  in 
  fragments. 
  Fracture 
  uneven 
  to 
  conchoidal 
  and 
  

   hackly. 
  Hardness 
  6. 
  Specific 
  gravity=2* 
  609 
  to 
  2*620. 
  Translucent 
  

   in 
  thin 
  laminse 
  to 
  transparent. 
  

  

  The 
  oblique 
  cleavage 
  in 
  the 
  direction 
  of 
  the 
  long 
  diagonal 
  is 
  charac 
  

   teristic 
  of 
  loxoclase, 
  although 
  not 
  always 
  very 
  distinct 
  ; 
  hence 
  its 
  name 
  

   The 
  sp. 
  gr. 
  is 
  also 
  higher 
  than 
  any 
  other 
  of 
  the 
  orthoclastic 
  feldspars 
  

   It 
  appears 
  subject 
  to 
  decay 
  by 
  exposure 
  to 
  the 
  atmosphere. 
  

  

  Composition. 
  (Mean 
  of 
  two 
  analyses,) 
  silica_63* 
  50 
  ; 
  alumina 
  20*29 
  

   oxide 
  of 
  iron 
  0*67; 
  potash 
  3*03; 
  soda 
  8*76; 
  lime 
  3*22; 
  water 
  -md 
  

   fluoride 
  of 
  silicon 
  1*23. 
  Fuses 
  before 
  the 
  blowpipe 
  with 
  difficulty 
  

   Heated 
  in 
  a 
  glass 
  bulb 
  it 
  gives 
  out 
  a 
  little 
  water 
  and 
  fluoride 
  of 
  silicon 
  

   and 
  is 
  very 
  imperfectly 
  decomposed 
  by 
  hot 
  muriatic 
  acid. 
  Poggen 
  

   dorff's 
  Annalen; 
  Phil. 
  Mag. 
  fy 
  Ann., 
  xxix., 
  p. 
  150, 
  Aug., 
  1S46. 
  

  

  MONAZITE. 
  

  

  This 
  mineral, 
  associated 
  with 
  sillimanite, 
  as 
  at 
  Chester, 
  Norwich 
  and 
  

   Saybrook, 
  Conn., 
  has 
  been 
  found 
  in 
  a 
  quarry 
  in 
  Yorktown, 
  Westches- 
  

   ter 
  county, 
  by 
  Mr. 
  J. 
  Mekeel. 
  The 
  monazite 
  is 
  in 
  very 
  perfect, 
  trans- 
  

   parent 
  prisms, 
  with 
  a 
  simple 
  pyramidal 
  termination 
  ; 
  the 
  crystals 
  are 
  

   small, 
  rarely 
  exceeding 
  one-eighth 
  of 
  an 
  inch 
  in 
  length, 
  and 
  are 
  scat- 
  

   tered 
  like 
  small 
  garnets 
  through 
  the 
  brown 
  quartz 
  adjoining 
  the 
  mag- 
  

   netic 
  iron 
  ore 
  which 
  is 
  an 
  associate 
  of 
  this 
  mineral. 
  Sill. 
  Jour, 
  xlvi, 
  

   p. 
  207. 
  

  

  NITRATE 
  OF 
  LIME. 
  

  

  This 
  is 
  said 
  to 
  be 
  found 
  in 
  Marbletown, 
  Ulster 
  county, 
  and 
  near 
  

   West 
  Point, 
  Orange 
  county. 
  Mather's 
  Rep. 
  on 
  the 
  Geol. 
  1st 
  Dist., 
  

   p. 
  85. 
  

  

  PHYLLITE. 
  

  

  This 
  is 
  a 
  mineral 
  which 
  was 
  first 
  found 
  by 
  Vanuxem, 
  in 
  the 
  town 
  of 
  

   Newport, 
  Rhode 
  Island. 
  It 
  is 
  in 
  the 
  form 
  of 
  black 
  shining 
  scales, 
  in 
  

   slate. 
  I 
  have 
  found 
  the 
  same 
  near 
  the 
  Clove 
  iron 
  mine, 
  in 
  Dutchess 
  

   county. 
  

  

  Composition. 
  According 
  to 
  Dr. 
  T. 
  Thomson, 
  the 
  constituents 
  of 
  

   phyllite 
  are 
  as 
  follows: 
  silica, 
  38*40; 
  alumina, 
  23*68; 
  peroxide 
  of 
  

   iron, 
  17*52; 
  magnesia, 
  8*96; 
  potash, 
  6*80; 
  water, 
  4*80. 
  

  

  It 
  is 
  thought 
  to 
  be 
  identical 
  with 
  the 
  ottrelite 
  of 
  Desclozeaux 
  and 
  

   Damour; 
  but 
  Thomson's 
  name 
  has 
  the 
  priority. 
  

  

  