421 
Corundum Stone from Asia. 
cyanite. The above could scarcely have happened, if the stones 
had been of sufficient size and value to require much examina- 
tion, the weight and degree of hardness being exceedingly de- 
ficient. The colour, therefore, will not be a safe guide. The 
diamond, whether white, blue, red, yellow, or green, can be 
distinguished by its crystal, or by its specific gravity and hard- 
ness, or, when it is polished, by its lustre. Other stones which 
"compose the order of gems, might equally depend on their crys- 
tallization, specific gravity, polish, and hardness, for a distinct- 
arrangement. The near relation of argil, which Bergman gave 
to this order, is daily confirmed ; and it will perhaps be to Mr. 
Klaproth, more than to any other existing chemist, that we 
shall owe our correct information on the subject of other gems, 
as we do on the subject of Corundum. 
Many of the varieties of Corundum, particularly the co- 
loured and transparent sorts, with their regular crystallizations, 
are yet desiderata. Many crystallized stones, from defect of 
colour, lustre, &c. are of little value in the market, such as, 
jargon, chrysolite, tourmaline; and an infinity of unnamed 
stones of Ceylon, Pegu, Siam, &c. would be valuable to the 
mineralogist, if obtained adhering to their strata, and in crys- 
tals whose external form is not obliterated. I have no doubt, 
when it is known how much such information will tend to 
illustrate the history of the earth, and particularly that of gems, 
the spirit of inquiry, so laudably afloat in British India, will 
be directed to attain it. 
i 
I have not heard of any metallic veins being found in Corun- 
dum, unless a stone which Alonso Barba, lib. i. c. 13. de- 
scribes, should give an instance. “ The Chumpi, so called 
“ from its grey colour, is a stone of the nature of emery, and 
