50 
A SYSTEM OF 
SECT. XLIV. 
B. Saphire, Saphyrtis gemma. 
It is tranfparent, of a blue colour, and 
is faid to be in hafdnefs next to the ruby,, 
or diamond. 
are found promifcuoufly mixed, having each their different 
forms, colours, and hardnefs, furnifhes a proof that nature 
forms the fo called precious ftones or gems, each from its par- 
ticular matter or principle. 
The round diamonds may be fuppofed to have undergone 
the fame fate with feme of the rock criftals, viz. to have 
been, by changes in the earth, broken from their beds, and 
by the agitation of waters, ground and rubbed againft one 
finother, until they have been rounded or reduced to this 
form; fince they are modly found amongft fand, and are dif- 
covered in places worn down by heavy fliowers of rain. 
The ruby is crillallifed into an o6loedral form, as well as 
the diamond and dijffers alfovery little from it in hardnefs 
and weight ; I have, therefore, coafidered thefe two, as be- 
ing of one and the fame kind, and that with as much right 
as others, who have ranked them under the rock criftais, 
which lall are more regular than any other earthy fubftance, 
as they affume, during their criftallifation, a determined 
form, viz. the hexagonal, with a point; at one or both ends. 
A fort of diamond is found, which is faid to be very fofc, 
and is called the Jargon f, but this fort is Hill unknown to 
me, nor have I found that any experiments have been made 
relating to its hardnefs and principles. 
I have feen in the coiledlion of the mine-mailer, M. Van 
Swab, a diaphanous aftoedral crlHal of Huor, which, ac- 
cording to thofe, who only mind the figure, ought to be 
called a Diamond. 
* What I have obferved about the o6^^oedraI form of the diamonds, 
may alfo be applied to the rubies. Befides, the rubies aie alfo fometimes 
found of ii regular hexagonal figures. E. 
•f The Jargon, ft) called by the Englifli jewellers. Its natural ihape is 
not yet known, it being found in form of pebbles in the Indies, where it 
is fplit into thin pieces, and thus fent to Europe. The jargons are of dif- 
ferent colours, viz. white, light yellow, and brown. According to 
feme lapidaries, they come neared to the faphires in hardnefs ; and as 
they have, when cut and polifbed, a great refemblance to tlte diamond, 
they are alfo by fome called Soft Diamonds, and one may eafily be im- 
pofed upon in purchaling thefe for true diamonds, when they are made 
in any fort of je v/el lei’s work, E, 
