﻿OF 
  DIAMONDS 
  IN 
  SOUTH 
  AFKICA. 
  55 
  

  

  It 
  is 
  of 
  greenish 
  or 
  yellowish 
  colour 
  ; 
  a 
  considerahle 
  portion 
  of 
  it 
  is 
  

   altered 
  into 
  serpentinous 
  material 
  ; 
  gradually, 
  as 
  the 
  depth 
  increases, 
  

   it 
  becomes 
  firmer. 
  For 
  a 
  depth 
  of 
  from 
  30 
  to 
  40 
  feet, 
  cracks, 
  

   joints, 
  and 
  irregular 
  cavities 
  filled 
  with 
  red 
  sand 
  from 
  the 
  surface 
  

   penetrate 
  ; 
  with 
  the 
  sand, 
  and 
  showing 
  that 
  it 
  has 
  come 
  from 
  the 
  

   surface, 
  are 
  fragments 
  of 
  ostrich-egg-shell, 
  small 
  rounded 
  grains 
  of 
  

   chalcedony, 
  agate, 
  &c, 
  identical 
  with 
  the 
  same 
  substances 
  mixed 
  with 
  

   the 
  surface-soil. 
  There 
  are 
  also 
  veins 
  of 
  calc-spar 
  and 
  nodules 
  of 
  

   iron 
  pyrites. 
  

  

  At 
  100 
  feet 
  in 
  depth, 
  at 
  Colesberg 
  Kopje, 
  the 
  rock 
  is 
  very 
  dark 
  

   in 
  colour, 
  much 
  more 
  compact, 
  and 
  less 
  altered 
  than 
  near 
  the 
  

   surface. 
  At 
  130 
  feet, 
  the 
  greatest 
  depth 
  so 
  far 
  attained, 
  the 
  rock 
  

   becomes 
  compact, 
  tough, 
  and 
  shows 
  the 
  original 
  texture, 
  though 
  

   the 
  constituents 
  are 
  altered, 
  notably 
  the 
  pyroxene 
  or 
  augite 
  into 
  

   bronzite*. 
  

  

  Prom 
  the 
  surface 
  down, 
  the 
  following 
  minerals 
  are 
  met 
  with 
  

   in 
  the 
  altered 
  rock, 
  viz. 
  garnet, 
  calc-spar, 
  mica, 
  bronzite, 
  augite, 
  

   diopside, 
  diallage, 
  iron 
  pyrites, 
  &e. 
  

  

  The 
  entangled 
  blocks 
  of 
  shale 
  and 
  sandstone 
  are 
  frequently 
  altered, 
  

   the 
  latter 
  sometimes 
  into 
  quartz 
  rock. 
  

  

  Disseminated 
  throughout 
  the 
  decomposed 
  rock, 
  diamonds 
  are 
  met 
  

   with, 
  from 
  the 
  enormous 
  size 
  of 
  over 
  150 
  carats 
  down 
  to 
  minute 
  ones 
  

   only 
  the 
  100th 
  of 
  a 
  carat 
  in 
  weight. 
  Still 
  smaller 
  ones 
  probably 
  

   occur, 
  but 
  are 
  too 
  minute 
  to 
  be 
  observed. 
  

  

  Many 
  of 
  the 
  diamonds 
  are 
  beautifully 
  formed 
  crystals 
  ; 
  but 
  a 
  large 
  

   percentage 
  consists 
  of 
  fragments 
  and 
  broken 
  crystals 
  ; 
  and 
  it 
  is 
  a 
  

   noticeable 
  fact 
  that 
  the 
  corresponding 
  pieces, 
  even 
  when 
  the 
  original 
  

   crystal 
  was 
  of 
  large 
  size, 
  are 
  never 
  found, 
  though 
  most 
  carefully 
  

   looked 
  for. 
  This 
  would 
  argue 
  very 
  forcibly 
  against 
  the 
  supposition 
  

   that 
  the 
  euphotide 
  (?) 
  rock 
  in 
  which 
  the 
  diamonds 
  are 
  now 
  found 
  is 
  

   their 
  original 
  matrix 
  or 
  " 
  mother 
  rock." 
  

  

  At 
  the 
  same 
  time, 
  it 
  is 
  marvellous 
  that 
  it 
  contains 
  such 
  a 
  rich 
  

   sprinkling 
  of 
  glittering 
  gems 
  if 
  not 
  the 
  original 
  matrix. 
  Colesberg 
  

   Kopje, 
  for 
  instance, 
  is 
  but 
  12| 
  acres 
  in 
  area, 
  and 
  has 
  been 
  dug 
  out 
  

   to 
  a 
  depth 
  of 
  from 
  80 
  to 
  90 
  feet, 
  yielding 
  some 
  millions' 
  worth 
  of 
  

   diamonds. 
  Some 
  of 
  the 
  claims 
  have 
  produced 
  immense 
  numbers 
  of 
  

   diamonds. 
  One 
  claim, 
  30 
  x 
  30 
  feet, 
  worked 
  out 
  to 
  a 
  depth 
  of 
  100 
  feet, 
  

   was 
  recently 
  sold 
  for 
  .£4000. 
  

  

  A 
  very 
  well 
  known 
  fact 
  on 
  the 
  diamond-fields, 
  and 
  one 
  rather 
  in 
  

   favour 
  of 
  the 
  euphotide 
  (?) 
  being 
  the 
  mother 
  rock, 
  is 
  that 
  each 
  of 
  the 
  

   pipes 
  furnishes 
  diamonds 
  easily 
  distinguishable 
  from 
  those 
  found 
  in 
  

   the 
  others. 
  Bultfontein 
  produces 
  small 
  white 
  stones, 
  occasionally 
  

   specked 
  and 
  flawed, 
  but 
  very 
  rarely 
  coloured 
  ; 
  while 
  Du 
  Toit's 
  Pan, 
  

   within 
  half 
  a 
  mile, 
  seldom 
  yields 
  other 
  than 
  coloured 
  stones. 
  So 
  

   well 
  marked 
  are 
  the 
  characteristics 
  of 
  the 
  diamonds 
  from 
  the 
  various 
  

   diggings, 
  that 
  diamond-buyers 
  can 
  generally 
  tell 
  by 
  the 
  appearance 
  

   of 
  a 
  stone 
  the 
  locality 
  it 
  has 
  come 
  from. 
  

  

  Denudation 
  has 
  effected 
  great 
  alterations 
  since 
  the 
  shales 
  were 
  so 
  

   completely 
  penetrated 
  by 
  igneous 
  matter 
  ; 
  it 
  is 
  therefore 
  not 
  so 
  

   * 
  Specimen 
  recently 
  sent 
  by 
  Sir 
  H. 
  Barkly. 
  

  

  