'A SYSTEM OF 
5 ^ 
by thofe who may happen to get an opportunity 
of difcovering the true methods to deliver the 
world from the many ambiguities and diflinc- 
tions, which have been made on this fubjedl, 
and which perhaps are all formed upon as great 
reafon, as thofe we ilill ufe in diftinguifliing the 
oriental and occidental gems, which fignifies in 
other words, no more than hard and clear, or 
foft and flawy, deeper or paler, or of good or bad 
colours 
* To the precious leones belong alfo che jacinths, of 
liyacinths, which are cridals harder than quartz crillals, 
tranfparent, of a fine reddifh yellow colour, when in their 
full ladre, and formed in. prifms pointed at both ends ; 
thefe points are always regular, in regard to the number of 
the facets, being four on each point, but the facets feldom 
tally : the Tides alfo, which form the main body, or column, 
are very uncertain, in regard both to their number and Hiape, 
for they are found of four, five, fix, feven, and fometimes of 
eight fides : further, the column or prifm is in fome alfo fo 
comprefled , as almofi; to refemble the face of a fphcrica! 
facetted garnet. Thefe criilals lofe their colour, become 
white, and do not melt in tfie fire, by which qualities 
chicfiy they may be diilinguifiied from garnets, (Sedlion 
Ixviii, 3.) w’hich are likewife fometimes found of a co- 
lour not inferior to the true jacinths. The author had not, 
at the time when he wrote this Effay, feen the true jacinths, 
but mentions in Sefllon Ixix. C. c, that the reddifh yellow 
garners frcm Greenland, are fold by the jewellers for jacinths ; 
fo are bkewife the Eaft Indian garnets of the fame colour, 
and, what is ftill more, there are fome jewellers that do not 
know the true diftindions between a jacinth and a garnet at 
Till, but buy and fell the garnets for jacinths, when they are 
of a fine reddifh yellow colour : this rnufi in particular be 
owing to the fcarcity of the true jacinth. 
Mr. Cronliedt has fince informed me by letter, that he had 
lately got fome jacinths of a quadrangular figure, w'hich did 
not melt; in the fire, but only became coloiirlefs ; this con- 
firms wliat 1 have already mentioned about the jacinths’ I 
tfipd, and which are above deferibed. E. 
SECT. 
