Little, H.
P.. An ancient reference to the emerald: Science, March 23, p. 291,
1917. The emerald was prized as a gem 5,500 years ago, according to the
translation of the oldest known Egyptian parchment manuscript, " The
instruction of Ptah-Hotep."
Pogue, J.
E., The emerald deposits of Muzo, Colombia: Am. Inst. Min. Eng. Bull.,
May, 1916, pp. 799-822. A complete description, illustrated with plates
and text figures, including location, history, geology, minerals, age,
origin, mining methods, production, other deposits, and selected
bibliography of the emerald deposits. These occur in calcite veins,
and the emerald " is one effect of a period of mineralization growing
out of the intrusion of a body of igneous rock." "The emerald was
deposited under gas-aqueous (pneumatolytic) conditions."
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The emerald in Spanish America: Pan American Union Bull., December,
1916. A general and historical description, well illustrated, of the
emerald mines of Colombia.
Riedl, Gustav, The
distinction of certain precious stones from their substitutes by
luminescence: Fachzeitsehr. Wein, Juwelrie, Gold-Silberschmiede, vol.
6, No. 1. pp. 1-6, No. 5, p. 8, 1914. The following abstract of this
article is quoted from Chemical Abstracts, vol. 10, No. 17, p. 2182,
Am. Chem. Soc, 1916. "The phenomena of luminescence in general are
discussed, and a combination of X-ray and cathode ray tubes described.
Natural ruby was found to be distinguishable from synthetic in that the
latter when exposed to cathode rays begins to glow more slowly, while
the glow persists after the current is interrupted. Burmese and Siamese
rubies can also be distinguished in that the latter do not respond to
ultra-violet light. Natural sapphires show in the cathode tube green or
red colors, whereas synthetic ones are blue or violet. Diamond glows
brilliantly in the cathode rays, and can be distinguished thereby from
all other colorless stones. Genuine emerald glows red in cathode rays,
while imitation emerald and other green gems remain green. The
luminescence phenomena of all known gems are tabulated, and the
practical application of the observations in the jewelry trade
discussed. An ultra-violet lamp is also described, and the effects
produced by its rays compared with those above referred to. Further
studies are in progress."
Wagner, P.
A.,. Recent diamond discoveries in the Transvaal: Min. Mag. (London),
October, 1916. (Abstracted from an article by P. A. Wagner in the South
African Min. Jour., July 15,1916.) Alluvial deposits of diamonds have
been found about 16 miles northeast of Pretoria, Transvaal, only a few
miles from the Premier mine.
