426 
THE  TROPICAL  AGRICULTURIST. 
[Dec.  i,  1 8c; 2 . 
but  greenish  or  bluish  by  transmitted  light,  when 
translucent,  and  either  in  distinct  crystals,  often  large, 
or  cleavable-massive.  It  is  ground  and  used  as  a 
polishing  material,  and  being  purer,  is  superior  in  this 
respect  to  emery.  It  was  thus  employed  in  ancient 
times,  both  in  India  and  Europe.  The  “Armenian 
stone”  is  supiiosed  by  King  to  have  been  corundum 
rather  than  emery. 
3.  Emery.  Schmirgel  Germ. — Includes  granular 
corundum,  of  black  or  grayish  black  color,  and  con- 
tains magnetite  or  hematite  intimately  mixed.  Some- 
times associated  with  iron  spinel  or  hercynite.  Feels 
and  looks  much  like  a black  fine-grained  iron  ore, 
which  it  was  long  considered  to  be.  There  are 
gradations  from  the  evenly  fine-grained  emery  to 
kinds  in  which  the  corundum  is  in  distinct  crystals. 
This  last  is  the  case  with  part  of  that  at  Chester, 
Massachusetts.  The  specific  gravity  varies  rather 
widely,  G.  = 3'75  — 4'31  Smith. 
Comp. — Alumina,  A1 2 0 3 = Oxygen  47T,  aluminium 
52'9  — 100.  The  crystallized  varieties  are  essentially 
pure ; analyses  of  emery  show  more  or  less  impurity, 
chiefly  magnetite. 
For  analyses,  etc.,  see  J.  L.  Smith,  Am.  J.  Sc., 
10,  354,  1850,  11,  53,  1851,  42,  83,  1866,  and  5th 
Ed.,  p.  139. 
Pyr.,  etc. — B.B.  unaltered ; slowly  dissolved  in  borax 
and  salt  of  phosphorus  to  a clear  glass,  which  is 
colorless  when  free  from  iron;  not  acted  upon  by 
soda.  The  finely  pulverized  mineral,  after  long 
heating  with  cobalt  solution,  gives  a beautiful  blue 
color.  Not  acted  upon  by  acids,  but  converted  into 
a soluble  compound  by  fusion  with  potassium 
bisulphate. 
Obs. — Usually  occurs  in  crystalline  rocks,  as  granu- 
lar limestone  or  dolomite,  gneiss,  granite,  mica  slate, 
chlorite  slate.  The  associated  minerals  often  include 
some  species  of  the  chlorite  group,  as  prochlorite, 
corundophilite,  margarite,  also  tourmaline,  spinel, 
cyanite,  diaspore,  and  a series  of  aluminous  minerals, 
in  part  produced  from  its  alteration.  Occasionally 
found  in  ejected  masses  enclosed  in  younger  volcanic 
rocks,  as  at  Kiinigswinter,  Niedermendig,  etc.  Rarely 
observed  as  a contact-mineral.  The  fine  sapphires 
are  usually  obtained  from  the  beds  of  rivers,  either 
in  modified  hexagonal  prisms  or  in  rolled  masses, 
accompanied  by  grains  of  magnetite,  and  several 
kinds  of  gems,  as  spinel,  etc.  The  emery  of  Asia 
Minor,  Dr.  Smith  states,  occurs  in  granular  limestone. 
The  best  rubies  come  from  the  mines  in  Upper 
Burma,  north  of  Mandalay,  in  an  area  covering  25 
to  30  square  miles,  of  which  Mogok  is  the  centre. 
Also  found  in  the  marble  hills  of  Sagyin,  16  miles 
north  of  Mandalay.  The  rubies  occur  m situ  in 
crystalline  limestone,  also  in  the  soil  of  the  hillsides 
and  in  gem-bearing  gravel.  All  the  crystallized 
varieties  of  the  species  occur  here;  the  spinel  ruby 
is  a common  associate.  A ruby  weighing  304  carats 
is  said  to  have  been  found  here  in  1890.  Rubies  and 
sapphires  have  also  been  reported  from  other  locali- 
ties, and  the  massive  varieties  are  common  especi- 
ally in  the  crystalline  rocks  of  Southern  India.  Ruby 
mines  have  also  been  worked  at  Jagdalak,  32  miles 
east  of  Kabul,  Afghanistan.  Some  fine  sapphires 
were  obtained  in  1882  from  the  Zanskar  range  of  the 
Kashmir  Himalayas  near  the  village  Machel  in 
Padar,  and  since  then  mining  has  been  carried  on 
there  with  some  success  (Mallet,  Min.  India ; La 
Touche,  Rec.  G.  Surv.  India,  23,  59,  1890).  Blue 
sapphires  are  brought  from  Ceylon,  often  as  rolled 
pebbles,  but  also  as  well-preserved  crystals.  Corun- 
dum occurs  in  the  Carnatic  on  the  Malabar  coast, 
on  the  Chantibun  hills  in  Siam,  and  elsewhere  in 
the  East  Indies ; also  near  Canton,  China.  At.  St. 
Gothard,  it  occurs  of  a red  or  blue  tinge  in  dolo- 
mite, and  near  Mozzo  in  Piedmont,  in  white  compact 
feldspar.  Adamantine  spar  is  met  with  in  large  coarse, 
hexagonal  pyramids  in  Gellivara,  Sweden. 
Emery  is  found  in  large  boulders  at  Naxos, 
Nicaria,  and  Samos  of  the  Grecian  islands;  also 
in  Asa  Minor,  12  m.  E.  of  Ephesus,  near  Gumuch- 
dagh,  where  it  was  discovered  in  situ  by  Dr.  J. 
Lawrence  Smith  associated  with  magarite,  choloritoid, 
yr  te,  caleite,  etc  ; and  also  at  Kulah,  Adula,  and 
lauser,  the  last  24  m.  N.  of  Smyrna;  also  with  the 
nacrite  (?)  of  Cumberland,  England.  Other  localities 
are  in  Bohemia,  near  Petschau;  in  the  Ural,  near 
Ekaterinburg;  and  in  the  Ilmen  mountains,  not  far 
from  Miask;  in  the  gold-washings  northeast  of 
Zlatoust  as  small  crystals  (called  soimonite  after 
Senator  Soimonov)  in  barsovite  (Kk.  Min.  Russl., 
1.  30, 2,  80.)  Corundum,  sapphires,  and  less  often 
rubies  occur  in  rolled  pebbles  in  the ' diamond  gravels 
on  the  Cudgegong  river,  at  Mudgee  and  other  points 
in  New  South  Wales. 
In  N.  America,  in  Maine,  at  Greenwood,  in  cryst. 
in  mica  schist,  with  beryl,  zircon,  lepidolite,  rare.  In 
Massachusetts,  at  Chester,  corundum  and  emery  in  a 
large  vein,  consisting  mainly  of  emery  and 
magnetite,  associated  with  diaspore,  ripidolite 
margarite  etc;  the  corundum  occasionally  in  blue 
pyramidal  crystals.  In  Connecticut,  at  W.  Farms, 
near  Litchfield,  in  pale  blue  crystals;  at  Norwich, 
with  sillimanite,  rare.  In  New  York,  at  Warwick, 
bluish  and  pink,  with  spinel,  and  often  in  its  cavi- 
ties; Amity,  white,  blue,  reddish  crystals,  with  spinel 
and  rutile  in  gran,  limestone.  Emery  with  magnetite 
and  green  spinel  (hercynite)  in  Westchester  Co.  in 
Cortlandt  township,  near  Cruger's  Station  and  else- 
where (Am.  J.  Sc.  33,  194,  1887.)  In  New  Jersey,  at 
Newton  blue  crystals  in  gran,  limestone,  with  grass- 
green  homblend,  mica,  tourmaline,  rare;  at  Vernon, 
near  State  line,  red  crystals,  often  several  inches 
long.  In  Pennsylvania,  in  Delaware,  Co.  in  Aston, 
near  Village  Green,  in  large  crystals;  at  Mineral  Hill, 
in  loose  cryst ; in  Chester  Co.,  at  Unionville,  abundant 
in  crystals,  some  masses  weighing  4,000  lb.,  and 
crystals  occasionally  4 in.  long  with  tourmaline, 
margarite,  and  albite;  in  large  crystals  loose  in  the  soil 
at  Shimersville,  Lehigh  Co.  In  Yinjina  in  the  mica 
schists  of  Bull  Mt.  Patrick  Oo. 
Common  at  many  points  along  a belt  extending 
from  Virgina  across  western  North  and  South 
Carolina  and  Georgia  to  Dudleyville,  Alabama ; 
especially  in  Madison,  Buncombe,  Haywood,  Jackson, 
Macon  Play  and  Gaston  counties  in  North  Carolina. 
The  localities  in  which  most  work  has  been  done  are 
the  Culsagee  mine,  Corundum  hill,  near  Franklin, 
Macon  Co.,  N.  C.,  and  26  miles  S.E.  of  this  at 
Laurel  Creek,  Ga.  The  corundum  occurs  in  beds  in 
chrysolite  (and  serpentine)  and  hornblendic  gneiss, 
associated  with  a species  of  the  chlorite  group,  also 
spinel,  etc , and  here  as  elsewhere  with  many 
minerals  resulting  from  its  alteration.  (Cf  Shepard, 
Am.  J.  Sc.  4,  109,  175  1872;  also  Genth,  1.  c.)  Fine  pink 
crystals  of  corundum  occur  at  Hiawassee,  Towns  Co.. 
Georgia. 
In  Colorado,  in  small  blue  crystals  in  mica  schist 
near  Salida,  Chaffee  Co.  Gem  sapphires  are  found 
near  Helena,  Montana,  in  gold- washings  and  in  bars 
in  the  Missouri  river,  especially  the  Eldorado  bar. 
In  California,  in  Los  Angeles  Co.,  in  the  drift  of  San 
Francisqueto  Pass.  In  Canada,  at  Burgess,  Ontario, 
red  and  blue  crystals. 
Ait.— Corundum  undergoes  extensive  alteration,  a 
series  of  aluminous  minerals  being  the  result.  The 
commonest  change  is  to  the  potash  mica  damourite, 
also  to  spinel,  cyanite,  fibrolite,  zoisite,  margarte, 
and  other  species.  Cf.  Gength,  Am.  Phil.  Soc.  13, 
361,  1873;  ibid  20,  381,  1882;  Am.  J.,  Sc.,  39,47,1890. 
Artie. — Formed  by  decomposing  potash  alum  by 
charcoal  (Gaudin);  in  crystals  by  exposing  to  a high 
heat  4 pts.  of  borax  and  1 of  alumina  (Ebelmen); 
by  subjecting  in  a carbon  vessel  aluminium  to 
the  action  of  boric  acid,  the  process  yielding  large 
rhombohedral  plates  (Deville  & Caron) ; by  addition 
to  the  last  of  chromium  fluoride  in  varying  amounts, 
affording  the  red  sapphire  or  blue  sapphire,  or  a 
fine  green  kind;  by  action  of  aluminium  chloride  on 
line  (Daubrde.)  Again  by  the  fusion  of  alumina  and 
mmium  ir.  siliceot3  earthen  crucibles,  yielding  a 
fusible  lead  aluminate  which  was  subsequently  de- 
composed by  the  silica,  setting  free  the  alumina  in 
hexagonal  crystals  of  considerable  size  (Fremy  and 
Feil);  under  varying  conditions  rubies,  sapphires, 
etc.,  being  obtained.  Also  by  the  decomposition  of 
aluminium  chloride  by  magnesium  and  water  vapor 
at  a high  temprature  in  a sealed  tube  (Meunier.)  1 f. 
Fouque-Lfivy,  Synth.  Min.,  218-224:  1882;  Bourgeois. 
Reprod.  Min.,  62,  1884. 
