CHAP. XIX.] THE PRECIOUS STONES OF CEYLON. 
419 
The precious stones occur in nearly every river valley which 
runs from the mountain heights in the interior of the island 
down to the low land. According to a statement by 
Mr. Tennent (i. p. 33), the river-sand at many places contains 
so much of the harder minerals that it may be used directly 
for the polishing of other stones. The same writer, or more 
correctly Dr. Gygax, who appears to have written the rather 
scanty mineralogical contributions to Tennent’s famous work, 
states that a more abundant yield ought to be obtained by 
working in the solid rock than by the usual method. This idea 
is completely opposed to the experience of mineralogy. The 
finest gems, the largest gold nuggets, as is well known, are 
never, or almost never, found in solid rock, but in loose earthy 
layers. In such layers in Ceylon the abundance of precious 
stones, that is to say, of minerals which are hard, translucent, 
and strongly lustrous, is very great, and enormous sums would 
be obtained if we could add up the value of the mass of 
precious stones which have been found here for thousands of 
years back. Already Marco Polo says of Ceylon: “ In ista 
insula nascuntur boni et nobiles rubini et non nascuntur in 
aliquo loco plus. Et hie nascuntur zafiri et topazii, ametisti, 
et aliqme alise petrse pretiosae, et rex istius insulae habet 
pulcriorem rubinum de mundo.” 
But some one perhaps will ask, where is the mother-rock of 
all these treasures in the soil of Ceylon ? The question is 
easily answered. All these minerals have once been imbedded 
in the granitic gneiss, which is the principal rock of the region. 
In speaking of granite or gneiss in southern lands, or at least 
in the southern lands we now visited, I must, in the first place, 
point out that these rocks next the surface of the earth in the 
south have a much greater resemblance to strata of sand, gravel, 
and clay than to our granite or gneiss rocks, the type of what 
is lasting, hard, and unchangeable. The high coast hills, which 
surround the Inland Sea of Japan, resemble, when seen from 
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