10 HINTS FOR OFFICERS IN THE DETECTION OF PRECIOUS STONES. 
day, a man who knows picks up one, tests it, and makes his fortune. 
My object in this paper is to show my brother officers, who may not 
have studied the subject, how very easy a matter it is to identify 
precious stones, with a minimum of trouble and apparatus. 
‘Few branches of knowledge are more universally neglected—it is hard 
to say why, unless from preconceived notions of the difficulty of the 
subject, which are quite unfounded. Hmanuel mentions a man. who 
disposed of a good business, and started for England to make his 
fortune by selling a parcel of “diamonds,” which turned out to be 
rock crystal! In 1889 much excitement was caused by the discovery 
of “rubies” at the Jasper mines in the Shan State of Momeik. The 
“ precious stones” were sent to Calcutta, and there found to be tour- 
malines! It is almost incredible that either of these mistakes should 
have occurred; and shows the extraordinary ignorance prevailing on 
the subject. I hope to make such errors impossible in the future—in 
any place, at least, where an artillery officer is stationed—and to show 
him how to identify any unusual crystal or pebble which he may 
pick up. 
For the present we may omit opaque stones. The only one of any 
value he is likely to find is turquoise, of which more anon. 
The first thing to do on finding a transparent stone, is to try if it 
can be scratched with the point of a good penknife. If it can, it is 
certainly not a precious stone, whatever its value mineralogically, and 
may be thrown away. 
If it resists the penknife, examine its colour, and compare with 
Table I. Colour alone will be seen to be very little guide. 
If the stone is very clear, look through it at a bright point of light. 
If two images of the light can be seen the stone can neither be a 
diamond, spinel, nor garnet. The converse however would be unsafe 
to go upon, as it is not very easy to see the two images with some 
double refraction crystals. 
Heat the stone and try if it will pick up minute fragments of paper 
or wood ashes, as a rubbed stick of sealing-wax will. If it does, the 
stone is probably a topaz or a tourmaline. The latter stone is called 
“aschentrekker’? by the Dutch, from this property. When found in 
large crystals with different shaped ends, it 1s excessively pyroelectric. 
Hiven this elementary test would have saved the Burmese Government 
some trouble and expense in the case of their “rubies.” A jargoon 
(zircon) acquires some electricity by heat, but not sufficient to form a 
good test. 
(Most precious stones acquire either positive or negative electricity 
by friction, but this is too common a property to be of much value, 
except to the professional jeweller). 
Take the stone into a perfectly dark room, and rub it briskly on 
cloth, wood or metal. If it phosphoresces it is certainly a diamond. 
No other stone possesses this remarkable property. Mr. G. F. Kunz 
says that all diamonds possess it, but I have not found it so. 
Hxamine the crystallization by Table IV., if the stone is a crystal. 
We cannot go much further without apparatus, but this may be of 
the simplest. Much may be done with a crystal of sapphire, and a 
