Burma Rubies show crimson and aurora-red images in the dichroscope.
In
Siam the Ruby is found near the coast at Krat and Chantabun, but the
stones are darker and more purple than the Burmese ones. Here again
granitic rocks and limestone are found, but the Ruby is so far only
known in the sands of this region. Siamese Rubies give dichroscope
images respectively crimson and brownish-red.
In
Ceylon Ruby is found in alluvial sands at the foot of Adam's Peak.
These sands for the most part are found in old river terraces ; a
crystalline dolomitic limestone is supposed to be the mother rock. The
stones are very clear but of a lighter colour.
In
India Ruby occurs but rarely in good quality, though the poorer
qualities are widely distributed. In Afghanistan to the east of Kabul,
Ruby is found in an altered limestone.
In
the United States, Ruby of gem quality is found at Corvee Creek, a
tributary of the Little Tennessee River in North Carolina, in a
decomposed garnetiferous basic rock ; many much weathered specimens
have been found, which have led Professor -Tudd and Mr. Hidden to
conclude that Rubies of very large size bave been formed here (Min. Mag., Vol. XII., p. 144).
In New South Wales a few small specimens have been found. Also at several places in Queensland.
The
associated minerals bear a close relationship in the different
localities. In Burma very fine Spinel, colourless Zircon, Garnets,
Apatite, different Felspars, Rubellite, Quartz, Muscovite and other
Micas, Lapis-Lazuli, Graphite, Scapolite, Pyrrhotite, and other
minerals are found, in
