XIX.] 
GEM DIGGINGS IN CEYLON. 
415 
the town of gems, where we were received with special kindness 
by Mr. Colin Murray, assistant government agent, I brought 
home a fine collection of the minerals of Ceylon. 
Precious stones occur in Ceylon mainly in sand beds, especially 
at places where streams of water have flowed which have rolled, 
crumbled down, and washed away a large part of the softer 
constituents of the sand, so that a gravel has been left remaining 
which contains considerably more of the harder precious stone 
layer than the original sandy strata, or the rock from which they 
originated. Where this natural washing ends, the gem collector 
begins. He searches for a suitable valley, digs down a greater 
or less depth from the surface to the layer of clay mixed with 
coarse sand resting on the rock, which experience has taught 
him to contain gems.^ At the washings which I saw, the 
clayey gravel was taken out of this layer and laid by the side of 
the hole until three or four cubic metres of it were collected. 
It was then carried, in shallow, bowl-formed baskets from half 
a metre to a metre in diameter, to a neighbouring river, where 
it was washed until all the clay was carried away from the sand. 
The gems were then picked out, a person with a glance of 
the eye examining the wet surface of the sand and collecting 
^ Emerson Tennent says on the subject:—The gem collectors penetrate 
through the recent strata of gravel to the depth of from ten to twenty 
feet in order to reach a lower deposit, distinguished by the name of Nellan, 
in which the objects of their search are found. This is of so early a 
formation that it underlies the present beds of rivers, and is generally 
separated from them or from the superincumbent gravel by a hard crust 
(called Kadiia), a few inches in thickness, and so consolidated as to have 
somewhat the appearance of laterite or sun-burnt brick. The nellan is for 
the most part horizontal, but occasionally it is raised into an incline as it 
approaches the base of the hills. It appears to have been deposited pre¬ 
vious to the eruption of the basalt, on which in some places it reclines, 
and to have undergone some alteration from the contact. It consists of 
water-worn pebbles firmly imbedded in clay, and occasional!}^ there occur 
large lumps of granite and gneiss, in the hollows under which, as well as 
in ‘‘ pockets ” in the clay (which from their shape the natives denominate 
“ elephants’ footsteps ”), gems are frequently found in groups, as if washed 
in by the current. (E. Tennent, Ceylon. London, 18G0, i. p. 34.) 
