ANAtysis. 249 



not always coincident. They are of a bright wax. yellow. Dsfciiption.and- 

 The (ides ot' the largeft of thefe fquare laminae is about a quar- ^fncra^i "fiom 

 icr of an inch. This laft fpecies is frequently found adhering Comwili, 

 to (he fides of quartz cry fiah, jn the cavities of granite. 



The other fpecies of this mineral confifts of an afPemblage 

 of crjilals clofely compacted together in the form of mam- 

 millary protuberances, in general, of the fize of fmall peas, 

 intimately connefled with each other. A (Iratum of thefe 

 about -J- of an inch thick, is fpread upon a layer of quartz, in 

 the cavities or filTures of a fpecies of compad granite. The 

 ftrise of which thete mamillae confift, diverge from a centre, 

 like zeolite. Some of the individual flriae, in forae cafes, over* ' ^ 



top their fellows, in thefe globular affemblages, and evidently 

 affume, on their pfojedling points, a cryftallized form. 



A, 



(1.) The detached cryflals of the former fpecies are eafily 

 reduced to powder, of a brilliant whitenefs. At the tem- 

 perature 56° of Fahrenheit, its fpecific gravity was found to 

 be 2,22. 



(2.) The hardnefs of the more corapaft fpecies is fufficient 

 to fcratch calcareous fpar. At the temperature 55°, its fpe-** 

 cific gravity was 2,253. It does not imbibe water. 



(3.) Some of the cryftals expofed, on charcoal, to the flame 

 of th^ blowpipe fuddenly and ftrongly driven upon them, 

 decrepitate : if they are gradually expofed to the flame thej 

 grow opaque, and become more light and tender ; but they 

 ihow no figns of fufion under the ftrongefl heat, 



(4.) The phofphate of foda and ammonia takes up a piece 

 of this mineral without effervefcence, but it fwims about the 

 fufed globule, unaltered. Borax diflblves a fragment of a 

 -Cryftal, and the globule remains tranfparent. 



(5.) Some of this mineral, reduced to a fine powder, was 

 mixed with about half its weight of pounded quartz, and 

 kneaded with water into a ball : but as foon as the mafs be- 

 came dry, all cohefion was deflroyed, and it fell into powder. 



(6.) Sulphuric acid, poured upon fome of it, caufed no 

 efiervefcence, nor was there any perceptible vapour extri- 

 cated. 



, .^.(7.) Some of the pulverized cryftals were put into a crucible 

 .^.platina, and fuiphuric acid was poured upon them. The 



. 5 crucible 



