jg6 Defer iptton of/ome new FoJfiU, 



and the fragments of it amorphous, yet angular and of {harp edges. The cryftals ate 

 hexahedral, fliort and thick columns, which fometimeSi from the different truncatures of 

 the edges, have the appearance of dodecagonal columns. Both fpecies are terminated in 

 tetrahedral pyramids. This ftone is feebly idio-eledlric, but not at all pyro-ele£lric. It 

 intumefces before the blow-pipe on the very firft. aftion of heat, frothing at the fame time, 

 and yielding a greyifli or yellowifti white glafs. With borax it efFervefces, foaming ftrongly, 

 and produces a grecniflr white pellucid glafs. It occurs at Langoe, a fmail ifland not far 

 from Krageroc, in Norway. 



Vir. ALLOCHROITE. 



Allochroite poflefles a yellow-grey, and, in fome inftances, a dark ftraw-yellow colour. 

 It has little luftre of the vitreous kind, which in the recent fradure pafles into that of wax. 

 It is opaque. Its fpecific .gravity is 3-5754. It is juft fcratched by quartz, gives fire with 

 fteel, and is not eafily broken by the blow of the hammer. Its texture is compaft, and 

 it is met with in large, thick flaty plates, with a decayed yellowifh-white furface. 

 Fradlure uneven, of the fmall and perfe£l conchoidal kind. Fragments angular and in- 

 determinate, not much fliarpened at the edges. It is infufible alone as well as with borat 

 of foda (borax). When treated with microcofmic fait (phofphate of foda and ammoniac)> 

 it exhibits an enamel-like, more or lefs perfe£tly fufed furface, which, on gradual cooling, 

 (hews at firft a reddifh-yellow, then a green of differently deep tints, and at laft a dirty 

 yellowifh-white colour. This change of colours feems to indicate fome metallic ingredients. 

 The native place of this ftone is the mine Wirum, in the vicinity of Drammen, ia 

 Norway. 



VIII. INDICOLITE. 



The colour of this ftone is a dark indigo-blue, a little lighter in the frafture, fo as to in- 

 cline to the azure or fky.blue. Its external luftre is vitreous in a high degree, approaching 

 to the metallic fplendor. It is untranfparent, and not very heavy. Its fpecific gravity 

 cannot be accurately afcertained, on account of the fmall cryftals bedded in it. Quartz is 

 a little fcratched by it. It is eafily broken. The ftreak is blueifh-grey. It feels cold and 

 dry like feld-fpar. Its texture appears to be corapaft ; but the longitudinal frafture is 

 finely ftriated, and the crofs frafture fomewhat uneven, palTing into the fmall conchoidal. 

 Its cryftals are rhomboidal columns, much ftriated lengthways. The fundamental form of 

 cryftallization feems to be quadrilateral ; but for the moft part thefe cryftals are polyhedral, 

 needle-fhaped and ftellular. It does not fufe before the blow-pipe. It is found near Uton, 

 in Sweden. 



l<iote. This foffil refemblcs in its colour the lazulite of ProfeiTor Klaproth, which I 

 know only by defcription : but as to its other phyfical and chemical charaders it differs 

 from it. 



(Tq he concluded in our nemt.) 



"^.—Experments 



