MINERALOGY. 



SECT. LX. 



6, The Sardonyx. 



Is a mixture of the chalcedony and car- 

 nelian, fometimes ftratum-wife, and fome- 

 times confufedly blended and mixed toge- 

 ther, 

 a. Striped with white and red ftrata : this 



ferves as well cut in cameo as the onyx. 

 £. White, with red dendrit.ical figures. 



This very much reiembles that agate 

 which is called the Mocha ftone, but with 

 this difference, that the figures are of a 

 red colour in this, inftead of black, as in 

 that agate. 



I have unwillingly diftinguifhed the 

 onyx, carnelian, chalcedony, fardonyx, 

 and agate, as feparate fpecies, fince there 

 is no real difference between them, except 

 ibme inexplicable degrees of hardnefs ; 

 but I have been induced to continue thefe 

 names for the reafons before given in 

 Seel:, liv. 



SECT. LXI. 



7. The Agate, Achates. 



This name is given to flints that are va- 

 riegated with different colours, promifcuoufly 

 blended together; and they are efteemed 

 in proportion to their mixture of colours, 

 their beauty and elegance. Hence alfo they 

 have obtained variety of names, moftly 

 Greek, as if the bufinefs of the lapidary in 

 cutting of them, and admiring their feveral 

 beauties and figures, had been derived from 

 that nation alone. 



F 2 As 



