C s 33 3 
IX. Description of the Corundum Stone, and its Varieties, com- 
monly known by the Names of Oriental Ruby, Sapphire, &c. ; 
with Observations on some other mineral Substances . By the 
Count de Bournon, F. R. S. 
Read March 25, 1802. 
"W" hen, in the year 1798, I presented to the Royal Society, 
in conjunction with Mr. Greville, a Paper on the Corundum 
Stone,* I gave some hints of an opinion which I, as well 
as Mr. Greville, had already formed, namely, that the said 
stone was absolutely of the same nature with those stones 
or gems which mineralogists, following the example of the 
jewellers, had hitherto distinguished by the epithet oriental . 
This opinion was founded upon circumstances which appeared 
to me perfectly satisfactory ; but these circumstances had not yet 
been sufficiently examined, nor were they sufficiently striking, to 
* See Phil. Trans, for 1798. p. 428. My principal intention, in the Paper here 
referred to, was, to bring together the various observations which had been then made 
respecting the stone here treated of. The great number of specimens which have 
Since been successively sent from different parts of the East Indies, have enabled me 
to form a more correct, and, in some respects, a different opinion of it. I therefore 
thought it would be of more advantage to science, instead of presenting to the Royal 
Society a supplement to my former Paper, to collect into one point of view, every 
information I could obtain upon the subject. I have consequently endeavoured, in 
the following Paper, to give, as far as I am able, a complete mineralogical history of 
this stone ; my former account being, when compared with this, a very imperfect 
®ne. 
