274 Count de Bournon's Description of 
of the stone, is observed to be situated in a part more or less 
near to its base ; a circumstance which considerably diminishes 
the beauty of the star-stone. The reflection which produces 
this effect, arises from the same cause as that of which we 
have already spoken, and proceeds from the same part of the 
stone ; consequently, when an oriental ruby, or a sapphire, 
which has the qualities necessary for the purpose, is intended 
by the lapidary to be formed into a star-stone, he ought to make 
his section pass below that part of the stone which he has found 
to correspond with the summit of the primitive rhomboid. As 
the kind of cutting most proper to produce this effect in the 
stone, is that rounded form which is called en cabochon , with 
as high an ellipsis as is possible, the lapidary ought, at the 
same time, to take great care that the summit of this ellipsis 
be situated exactly under the point which corresponds with the 
summit of the rhomboid ; in that case, the light reflected in 
the interval of the laminae upon the three edges of the primi- 
tive rhomboid, and upon the middle of its three faces, will trace 
upon the stone, a star, the six rays of which will include the 
circumference of the rounded part, or ellipsis. The same effect 
may also be made to take place on one of the solid angles of 
the base, but in a much less perfect manner. 
I have met with many fragments of sapphires, as well as of 
oriental rubies, which naturally produced the effect here spoken 
of, in consequence of their having been broken, by chance, in 
a manner proper to occasion it ; that is, they were broken, ac- 
cidentally, in a direction contrary to that of the laminae, and 
perpendicular to an axis passing through the two summits of 
the pyramid of the primitive rhomboid ; after which, the frag- 
ment had been a little rounded by friction. 
