628.  This  valuable  metal  is  found  only  in  the  metallic  oi
native  state,~"being' very  widely  diflFused  in  small  quantities
iiTme  older  rocks.  From  these,  by  the  action  of  various
causes,  it  finds  its  way  into  the  sand  of  rivers,  and  is  dis-
tributed in, small  quantities,  in  many  widespread  deposits
of  coarse  gravel  or  shingle,  as  in  Alta  California,  Australia,
on  the  eastern  flanks  of  the  Ural  mountains,  and  over  a  wide
belt  of  country  in  Virginia,  the  Carolinas,  Georgia,  and  Ala-
bama. These  diluvial  deposits  furnish  nearly  all  the  gold
of  commerce,  by  the  process  of  washing  and  amalgamation
with  mercury.  Large  masses  of  gold  sometimes  occur,  as
one  of  twenty-eight  pounds  in  North  Carolina.  In  Si-
beria a  mass  was  found,  now  in  the  Imperial  Cabinet  of  St.
Petersburg,  weighing  nearly  eighty  English  pounds.  Several
of  still  greater  size,  mingled  with  quartz,  have  been  found
in  California.  Generally,  however,  it  occurs  only  in  minute
rounded  and  flattened  grains  or  scales.  It  is  also  found  in
veins  of  quartz,  in  compact  limestone,  and  distributed  in
iron  pyrites.  Native  gold  is  usually  alloyed  with  from  5
to  15  per  cent,  of  silver.  Since  the  discovery  of  gold  in
California,  in  3Iarch  IS-tT,  it  is  estimated  that  at  least  fifty
millions  of  dollars  have  been  annually  obtained  there,  chiefly
from  the  auriferous  sands  of  those  regions.
629.  Gold  is  distinguished  by  its  splendid  yellow  color,
its  brilliancy,  and  freedom  from  oxidation,  by  its  extreme
malleability  and  ductility,  by  its  high  specific  gravity,  (19-26
to  19-5,)  and  by  its  indifference  to  nearly  all  reagents.     It


What  is  the  arhor  Diance  ?    628.  ITow  does  gold  occut  in  nature?    How
ta  it  oL tain ed?    What  of  California ?     629.  Describe  this  metal?


872  METALLIC  ELEMENTS.
