MINERALOGY. 43 



have been called Marble, although the Italian 

 mafon himfelf knows extremely well how to dit- 

 tinguifh a Marble, a Jafper, and a Granite, from 

 one another, giving the two laft names only to 

 marbles of fuch colours as thofe fpecies generally 

 have, when he either cannot get any real ones of 

 thofe harder ftones, or will not give himfelf the 

 trouble to polifh them. This confufion in the 

 names may, however, in regard to this fyftem be 

 tolerated, fince thefe three different fpecies of 

 ftones, viz. the limeftones, the jafpers, and the 

 granites, are here feparately defcribed: but fince 

 thev cannot all be worked in a like manner, nor 

 do they equally refill: the violence of time, they 

 deferve to be known by the architects in a clearer 

 manner, and by feparate names. 



A yet lefs confufion is that of the Saxum, which, 

 tho' compounded of limeftone and ferpentine *, is 

 called Marble, not only when it contains a greater 

 quantity of the limeftone, as the marble from 

 Kolmordcn in the province of Oftrogottland, but 

 alfo when the ferpentine predominates, as in the 

 marble called Pozzevera de Genoua^ and alfo a 

 kind of green marble from Spain, becaufe this 

 kind of ftone is as eafy to cut and work as a true 

 marble, although the ferpentine is fomewhat 

 fjfcer ', and eafier to pciifh. 



The calcareous fpar (Sect, x.), and its cryftalli- 

 fations Seel, xi ), are more difficult to be burnt 

 into lime, than other limeftones ; they are there- 

 fore of no great ufe in architecture, any further 

 than that they may be employed in making grot- 

 tos : Nature has alfo made the quantity of this 

 kind proportionable to its ufe. 



* What o'lr Author calls Serpentine, is a fpecies ofne* 

 ph;i:ic, and of" (be ciafs of Talcs. D. C 



But 



