|}2 6 Count de Bournon's Description , &c. 
in the part of the rock opposite to that wherein I discovered the 
blue substance already described. The Abb£ Hauy, in his Mi- 
neralogy, (Vol. IV. page 36 1,) mentions these emeralds, but 
expresses some doubts respecting them. These doubts I think 
would be removed, if I had it in my power to send him the 
specimens I then collected. Among them were some crystals, 
which possessed a degree of hardness fully equal to that which 
is known to belong to the emerald : the hardness of many others 
was, however, very inferior ; owing no doubt to the interposition 
of some heterogeneous substance, which I always suspected to 
be of a magnesian nature. 
The Abb6 Hauy, in order to fix his opinion respecting this 
substance, appears to require nothing but to see some crystals 
of it which possess the additional facets peculiar to the true 
emerald. I cannot indeed shew him such crystals; but I can 
supply the want of them, not only by my notes, but also by 
models cut in wood, which I was so fortunate as to bring away 
with me, as well as the whole collection of models of which 
they form a part. I find, among the models I made of these 
emeralds from Forez, all the varieties the Abb6 Hauy has re- 
presented in Plate XLV. of his work, excepting only r ig. go-, 
of that Plate. 
