ti 



A SYSTEM OF 



by thofe who may happen to get an opportunity 

 of difcovering the true methods to deliver the 

 world from the many ambiguities and diftinc^ 

 tions, which have been made on this fubjecl, 

 and which perhaps are all formed upon as great 

 reaibn, as thofe we (till ufe in diftinguifhinsr 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 ftones belong alfo the jacinths, or 

 Iiyacinths, which are criftals harder than quartz criftals, 

 tranfparent, of a fine reddijh yellow colour, when in their 

 full luilre, and formed in prifms pointed at both ends i 

 thefe points are always regular, in regard to the number of 

 the facets, being four on each point, but the facets feldom 

 tally : the fides alfo, which form the main body, or column, 

 are very uncertain, in regard both to their number and fhape, 

 for they are found of four, five, fix, feven, and fometimes of 

 eight fides : further, the column or prifm is in feme alfo fo 

 CompicfTed , as almoff. to referable the face of a fpherical 

 Facetted garnet. Thcfe criftals lofe their colour, become 

 white, and do not melt in the fire, by which qualities 

 chiefly they may be distinguished from garnets, (Seclion 

 Ixviii. 3.) which are likewife fometimes found of a co- 

 Jour not inferior to the true jacinths. The author had not, 

 at the time when he wrote this EfTay, feen the true jacinths, 

 but mentions in Section Ixix. C. c. that the reddifii yellow 

 garnets from Greenland, are fold by the jewellers for jacinths ; 

 fo arc likewife the Eall Indian garnets of the fame colour, 

 and, what is flill more, there are fome jewellers that do nof 

 know the true diftinctions between a jacinth and a garnet at 

 all, but buy and fell the garnets for jacinths, when they are 

 of a fine red dim. yellow colour : this mult in paiticular be 

 pwing to the fcaicity of the true jacinth. 



Mr. Cfpn.ftedt has fince informed me by letter, that he had 

 lately got fome jacinths of a quadrangular figure, which did 

 mot itm-Ic in the fire, but only became colourlefs ; th;6 con- 

 firms what J have already mentioned about the jacinths I 

 friccs and which are above defcribed* E. 



SECT, 



