of that character has been since verified, but no discovery of diamonds in it has been reported.
As
in all other alluvial deposits, the diamonds are accompanied by
pebbles of a siliceous nature and also by a form of blue or bluish-gray
corundum which is regarded by the natives as a sure indication of the
presence of diamonds. This companion of the " Prince," as the diamond
is termed, is known as Ba tu timahan. It is not of a quality to cut for
jewels, and was long thought to be a form of quartz. Like the black
tourmaline or " jetstone " of the Bingara fields of Australia, its
chief value in the eyes of the miners is that it assures them of the
presence of the more precious gem.
Mining
is carried on by Malays and Chinese, the latter being skillful and
economical miners. A French company secured a 25-year concession in
1882 to work a tract of about 5,000 acres near Tjampaka in the
Tanahlaut or Martapura district, but work was discontinued in about a
year after operations began. Apparently, the deposits are not
sufficiently rich and the location of paying dia-mondiferous material
too uncertain, to warrant risking the expense of a thoroughly equipped
mining organization. Even the skill and economy of the Chinese fail at
times to win enough to hold them to the work, and the diamond diggings
are deserted for the neighboring goldfields, from which returns are
more sure. At times, however, there is great activity. In a few weeks
of 1905, 1,278 licenses were taken out in Martapura.
Most
of the crystals are octahedrons and dodecahedrons. The natives call
the former " perfect stones," and simply polish the native facets; when
the angles are sharp and the facets bright, they are called " intan men-
