-'194 D'efcript'ton of fotne new Fojftts. 



If two of thefe plates be rubbed upon each other, they are a little phofphorefcent, and emit 

 a fmell refembling that of quartz by friftion. Acanthicone is in fome degree pyro- 

 eleftrical. Before the blow-pipe upon charcoal it readily fufes, with efFervefcence, into a 

 blackifh fcoria replete with air-bubbles. In the cold it is infoluble in the fulphuric and 

 nitric acids. This foflll occurs in the Swedifli iron-mines, near Perlberg, Lengbanfliytta, 

 and Norberg ; but in Norway very beautiful fpecimens of it are met with in the Kulftad- 

 mines at Helgoland, and near Arendal in the iron-mines Tornbiornfbo, Ulrica, Not- 

 bro, &c. Till now it was miftaken, or confounded with fchorl, or with green garnets* 

 Some cryftals are fo large as to weigh five pounds. 



II. SPODUMENE. 



The colour Is commonly a greenifh-white of various (hades. The luftre that of the 

 mother-of-pearl. In the fubftance itfelf it is little tranfparent, but much fo on the edges. 

 Its fpecific gravity is 3.218. It fcratches glafs, but is itfelf fcratched by quartz, and affords 

 a white' powder. It feels colder than quartz, yet dry and fmooth. Spodumene is not at 

 all eledric, nor phofphorefcent ; nor does it afford a quartzy fmell by fri£lion. Its texture 

 is lamellar, with a double croffing. Its perfedl fragments are rhomboidal acute-angled 

 prifms (120° and 55°). The fragments of the crofs-fra£lure are for the moft part longilh 

 plates, that have their edges but little Iharpened. When fubjedled to the blow-pipe upon 

 charcoal, it becomes, at the firft gentle impreffion of heat, opaque, dull, and yellowifli ; 

 then developes itfelf in the dircdtion of its laminje, at the fame time that it fwells a little, 

 falling afterwards into an infipid powder, which by a ftronger heat affords a very tranf- 

 parent greenilh-white glafs. Nitric acid does not diffolve it, nor produce any effervefcence. 

 It is found, together with feveral other foflils, in the remarkable formation of iron at Uton, 

 in Skarrgarde, three miles from Dalero. 



III. SAHLITE. 



Its principal colour is a pale afparagus green of various fliades. Its external luftre 

 ▼Itreous, inclining to wax, but internally it has little fplendor. It is tranfparent, and 

 fometimes femi-pellucid, if the cryftals are pure, and -have fuffered no decay. Specific 

 gravity 3:.2368. Sahlite barely marks glafs, and does not ftrike fire with the fteel, and is 

 eafily broken. Its texture prefents ftjraight and fmooth lamellse, thrice croffing each other 

 in a fomewhat acute-angled direCllon. The fragments of the crofs-fradturc are roundilh* 

 Their form of aggregation is of the coarfe-grained kind, and fometimes, if the ftone be in 

 lumps or maffes, they are hamated, or indented into each other. This ftone occurs in 

 cryftals of redlangular, quadrilateral columns, the lateral edges of which are flightly 

 truncated, and convex. The broad terminating edges of thefe columns are flightly trun- 

 cated. The ftreak by rafure is white. This ftone is fomewhat foft. and idio-eleftric. 

 When rubbed upon a piece of the fame kind, it emits no odour, nor fliews any phofphor- 

 4 . efccneei 



