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Ch. 2: Gems in Ceylon

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GOLD AND GEMS.
283
5.    The quartz being in crystalline condition is not a sign of its containing no gold. See No. 12.
6.    The visibility of gold is worth nil for Nos. I, 5 aQd 8, are rich in gold. It has recently been stated that assayers are of no use. We are told we must be able to see and judge by the eye as to whether a quartz reef •will pay and that it is a poor tale to have it tested. However such statements are not worth much. If we see the gold and know that it extends in the quartz, we then know without assay that it will pay and its extraction may be at once begun with.
Assaying of fair samples is very necessary. There is not sufficient sight-evidence in many varieties of quartz to warrant gold being there in paying quantity. Even the rough amalgamation process, so commonly used by the miner is unreliable where the gold occurs with pyrites. Nor can the amalgamation process be successfully used for its extraction in such cases, e. g., three samples of auriferous pyrites were operated upon not long ago.
(a) From Siberia which contained 100 grams to the ton. (4) „ Venezuela              ,,          300             
(c) „ California                        150             
The first yielded all its gold by amalgamation. The two others, both in the raw state and after roasting, yielded only insignificant quantities. From further experiment, it was inferred that the presence of antimony and arsenic prevent amalgamation.
The tailings of old^ines are now being re-worked by the " Chlorine pro­cess " or by the still better method devised by Mr. W. A. Dixon. See " Direc­tions for extracting gold, silver, and other metals from pyrites." Proceedings of tlu Royal Society, vol. 20.
Ceylon quartz is rather too glossy in appearance and from many localities is destitute of metal of any kind, or having caverns either empty or filled with earthy matter. The pyrites are of too brassy a nature. However, we have quartz partak­ing of the character of Nos. 6 and 16 in Hewaheta and Ramboda. A some­what similar quartz to 10 and 15 occurs in Balangoda and the district around.
In the Nawalapitiya district, we have a quartz partaking of the nature of II, 12, 13, but no metal is visible. The mineral galena, mispickel and blende have not been recorded up to the present time as occurring in this island.
Mr. Dixon, we know, has judged rightly in stating that the mere colour of quartz is no certain criterion of its value. We took with us to Melbourne a specimen of gold-bearing quartz from the Alpha Mine in Southern India, and, judging by what we had seen in Devalah, we expected to find the specimens of Australian gold-bearing quartz sent to the Melbourne Exhibition full of pyrites and rusty coloured. Some such quartz we did find exhibited, but the leading specimens (some of them immense blocks) were pure white, shading away to grey). A person acquainted with only the surface quartz of Devalah would certainly never have suspected the existence of gold in pure white and occa­sionally crystalline quartz. The uneducated eye, therefore, is here at fault, but the merest tyro soon learns the value of " Black Jack," or blende as an indic­ation of the presence of gold, equally with mundic (iron or arsenical pyrites) and galena. Blende, Mr. Dixon explains, is a sulphide of zinc, while galena is composed mainly of sulphide of lead; sometimes rich in sulphide of silver. We suspect that neither " black Jack" nor galena exist in Ceylon, any more than the special " Lower Silurian" slate formations so strongly insisted on in Victoria. But " mispickel," which Mr. Dixon describes as arsenical iron pyrites, ought surely to exist. The first great revolution in the search for gold was the discovery that hundreds and even thousands of feet below the alluvials of Mount Alexander, Bendigo, Ballarat, Arrarat, and other once rich but entirely or partially exhausted gold fields, and underlying enormous masses of the basaltic rock known locally as " blue stone," vast stores of the precious metal lay hidden. It is found either in situ in the old quartz and slate formations, or
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