HINTS FOR OFFICERS IN THE DETECTION OF PRECIOUS STONES, let 
crystal of quartz, which any jeweller—Mr. Streeter of Bond Street for 
choice—would supply for a nominal sum—say ls. very officer pro- 
ceeding abroad, who wishes to search for precious stones, should pro- 
vide himself with—at least—this most light and inexpensive outfit, 
and have a little box made to hold the crystals. 
With these alone we can do a great deal. Refer to Table II. and 
study the comparative hardness of stones. A stone of hardness 5 can 
just be scratched with a good penknife. 
The unknown stone can first be tested by trying if it will scratch 
glass—a sharp point of the stone being chosen for the purpose. It is 
a good thing to carry a bit of hard flint glass for this experiment. 
Tf it does not scratch glass and cannot be scratched with a penknife, 
it is probably apophyllite, and more of a curiosity than a gem stone. 
If it scratches glass feebly it might be epidote, moonstone, axinite, 
sphene, etc. None of these stones are of much value, except the 
Bobrowska garnet, which is very unlikely to turn up anywhere that 
the artillery officer may be quartered, and the precious opal, which 
is unmistakable and needs no test at all. 
If the stone scratches glass and is scratched by quartz, it is possibly 
peridot or chrysolite. Observe the colour. Good stones of peridot 
would fetch a good price at present. 
Now take your crystal of sapphire and try its point on your stone. If 
it does not scratch it and is scratched by it, the stone is a diamond 
beyond all doubt. Ifit does not scratch it, and is not scratched by it, 
it is a form of corundum. 
The corundum gems are, according to colour, sapphire, ruby, white 
sapphire, oriental topaz, oriental emerald (very rare), oriental amethyst. 
Of these the white sapphire is of little value. So is the oriental 
topaz, simply because the public distinguish not between this fine stone, 
the Brazilian topaz, and yellow rock crystal. The same may be said of 
the oriental amethyst, though a fine specimen might be perhaps sold. 
The oriental emerald is very rare, and would fetch a high price. The 
value of the sapphire and ruby depends chiefly on their shade of colour. 
That of the costliest sapphires is the blue of the corncockle flower, that 
of the ruby the red of a drop of pigeon’s blood on white paper. But 
where one corundum crystal is found, others may be; and the colouring 
is simply a matter of homceopathic quantities of material which defy 
analysis by their minuteness. So the searcher need not be discouraged 
if his crystal is white, yellow or violet. 
This is about as much as an officer can do with his two testing 
crystals, but it is already a good deal to accomplish with tools costing 
about a shilling, and weighing, say, half an ounce. He is now in a 
position to identify the diamond, ruby and sapphire. Surely everyone 
ordered abroad might well take with him so portable and inexpensive 
an apparatus, and spend a few idle hours in searching unfrequented 
spots, pebble beaches and such like, with the chance of a great reward! 
If all R.A. officers did so, I am pretty sure that some fortunes would 
be made, and that a large addition to our mineralogical knowledge—if 
not to the wealth of Hngland—would accrue. 
It will be observed that sapphire is just a trifle harder than the 
