day
bleached sapphires in such perfection, that they might be taken for the
finest diamonds. Fragments of blue sapphire of indifferent quality have
been found as large as a goose's egg. The purple variety or the
oriental amethyst is rare. A green variety is still rarer, and when
found, perhaps, owes its colour to a blending of blue and yellow, two
colours of frequent occurrence in the same stone. The black sapphire is
no less rare. It is not uncommon to find some other mineral included in
the substance of the sapphire, such as crystals of iron glance, or a
small mass of crystallized mica. Corundum is less frequently met with
than the sapphire, being rarely, found except in Uva, where it is found
in the bed and in the banks of a small stream; the sand, gravel, and
pebbles among which the corundum occurs, in their nature correspond
with varieties of granite, gneiss and hornblende rock. The corundum is
often found in large six-sided prisms, it is commonly of a brown
colour, whence it is called by the natives koroondu gala (cinnamon
stone). Occasionally it is to be met with partially or entirely covered
with a black crust, perhaps merely the stone with an unusual proportion
of iron. The corundum and sapphire are so closely akin, that the
natives have even observed the similarity. The two minerals are linked
together by the coarse and opaque varieties of the latter, which are
common enough in Saffragam'. Chrysoberyl is of very rare occurrence,
and is said to be brought from Saffragam.' The more perfect crystals of
all the varieties of ruby, sapphire, corundum and chrysoberyl,
exhibiting in every direction smooth facets like the garnet, the
diamond, and so many other minerals, seem to shew that they are
contemporaneous in their formation with the rock from whence they are
derived ; that they have crystallized in its substance; and that they
are not detached till it undergoes distinegration or decomposition,
when they are washed by the heavy rains and torrents with the detritus
of their parent rock to lower ground to reward the perseverance of the
native explorers who might search in vain in the mountain mass.
Corundum is the only species of this family that is not esteemed as a
gem, and the only one that is applied to any purpose of utility. In its
powdered state it is extensively employed by the lapidary in cutting
and polishing stones, and by the armourer in polishing arms. It enters,
too, into the compositions of an excellent hone made by natives,
consisting chiefly of this mineral in very fine powder, and of kapitia
a peculiar kind of resin.
Of
the felspar family, it is highly probable that several species exist in
the island. Tablespar has been already alluded to, and the subdivisions
of felspar viz, adularia (including glassy felspar),
Labrador-stone, common felspar, and compact felspar. These minerals are
common in gneiss and granitic rock, with the exception of Labrador
stone, which is seldom found, and then in a bed of graphic granite.
Adularia is very abundant in some parts of the interior, particularly
in the neighbourhood of Kandy, where it is occasionally the
predominating ingredient of the rock.
Of
the hornblende family, two species occur, common hornblende, the
constituent of the rock of this name and glassy tremolite which has
been observed at Trincomalee in a narrow vein of quartz in gneiss.
Pitchstone
is perhaps the only mineral of the family of this name to be found in
Ceylon, a small vein of it occurs near Trincomalee in granite. Mica or
glimmer (Miniran, Singh.), as a constituent part of granite and
gneiss is abundant, besides, it often occurs in large plates imbedded
in these rocks. It is collected by the natives, who use it for purposes
of ordinary decoration, and for ornamenting talipot parapluies. Common
chlorite is occasionally to be met with both at Galle and Trincomalee
disseminated through quartz. Green earth is more rare; it is found in
Lower Uva, where it is pretty abundant near Alipoot in small veins, and
includes masses in clay derived from the decomposition of a granitic
rock. This mineral is of an unusually light colour, varying from green
to light apple-green.
Magnesian minerals are far from abundant in Ceylon, and are perhaps
confined to dolomite, carbonate of magnesia, and talc. The very rare mineral
native carbonate of magnesia, has been discovered in a nitre cave, accora.
