. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. 276 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES the nature of basalt, which is the principal, if not the sole, constituent of the hill ranges. The gem-gravels are made up of fragments of this rock, and the separating layer of tenacioUvS grey, brown, or yellow clay is also, in all probability, a decomposition product of. rs «9 CART ROAOa ^'^- PATHS'
. Precious stones, a popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewellers, etc. With an appendix on pearls and coral. Precious stones; Pearls; Corals. 276 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES the nature of basalt, which is the principal, if not the sole, constituent of the hill ranges. The gem-gravels are made up of fragments of this rock, and the separating layer of tenacioUvS grey, brown, or yellow clay is also, in all probability, a decomposition product of. rs «9 CART ROAOa ^'^- PATHS' -â ' BOUNOARIES*-^**..-* QAN(aJVILLAaG KLONO (M) RIVER WAT, TEKIPLE t/ULr leaS HXNRY LOUIS Fig. 56. Euby and sapphire mines of Muang Klung in Siam. the same rock. On these grounds it is concluded that the basaltic trap-rock is here the mother-rock of the ruby; this conclusion, however, requires the support of further evidence. The gem-bearing layer varies in thickness from 10 inches to 5 feet, and is overlain by a sandy and clayey deposit from 2| to 12 feet thick, containing no precious stones. In the clayey gravel are found ruby and sapphire, as well as common corundum ; quartz, in good transparent crystals, and crystals of zircon and ilmenite are abundant, while topaz is very rare. Of these minerals, the first two only are commercially valuable and sought after by the miners. Rubies are much more frequently met with than are sapphires, the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bauer, Max, 1844-1917; Spencer, Leonard James, 1870- tr. London, C. Griffin and Company, Ltd.
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