]92 0F THE ANHYDROUS SULPHATE Of LIME, 



Groups of cry- In the Tyrolefe fpccimens, fimilar to that which afforded 

 ftai9 » the cryftals which I have juit defcribed, thefe are for the 



moil part ftrongly engaged and applied againit each other, 

 eroding each other in different directions ; fome of them, how- 

 ever, are infulated. But as many of them are united by their 

 broad i ih or pearly faces, they have no very (hong adhefion, 

 and it is always fufficiently eafy to feparate them with the 

 eafily fcparated. edge of a knife. Thefe fpecimens frequently exhibit in their 

 mafs more or lefs confiderable portions of pure common fait; 

 feveral of their cryftals are conliderably transparent. 

 Peculiarity. A piece of this fubftance which I procured for Mr. Chene- 



f hSf r afwiti- V ^ for the purpofe of analyfmg it, exhibited a peculiarity 

 mouy and which deferves to be remarked. On breaking fome of its 



quartz. cryftals, fmall needles of fulphuret of antimony were per- 



ceived within it, adhering for the moil part to fmall groups of 

 cryftals of quartz. Not a trace of either of thefe two fub- 

 flances was found in the other parts that were Subjected to 

 analyiis : the tame was the cafe with the carbonate of lime, 

 which Mr. Klaproth has indicated at T y o - of the analyfis 

 which he made of it, and which, undoubtedly, was likewife 

 only an extraneous or interpofed fubftance. 

 Quarts in an- In like manner, in the i'ione of Vulpino, obferved and de- 



or.hev fpecimen. ^j^j s ^ accurately and care f u H y by Meffrs. Fleurieu and 



Bellevue, in the 2d Vol. of the journal de Phyfiquefor 1798, 

 the anhydrous fulphate of lime is mixed with interpofed par- 

 ticles of quartz, which, according to the analyiis made of it 

 by Mr. Vauquelin, are in the proportion of -l^- 6 to its whole 

 mafs. I am indebted to the friendfhip of Mr. Fleurieu for 

 two fpecimens, which prefent two diftinci varieties of this 

 interesting flone. 



One of them is of a good blue colour, is partly of a very 

 fine fandy grain, and partly coarfer and lamellated : it greatly 

 refembies the carbonate of lime known by the name of faline 

 marble. An immenfe number of fmall lam inas are obfervable 

 in it, which crofs each other in different direct ions, and are 

 found by the magnifier to be perfect ly rectangular. 



The other is of a darker afli coloured grey ; it is lefs pure 

 than the former : fome portions of a true gypfeous eaith are 

 obferved in it, containing a fmall quantity of argill and of 

 carbonate of lime. Its fubftance is more compact than that of 



the 



