382 On the Geological Structure of the Vicinity oj" Dublin. 



it which traverses granite, observed by himself in the island 

 of Arran * . 



8. JVaveU'te. This remarkable mineral has recently 

 been found in the county of Cork, at Springhill, near 

 T)-actonoLlei/, about tesi tniles south-eastward from the 

 city. The Rev. Mr. Hincks, ot the Cork Institution, who 

 has been so i.ind as to send me some specimens of it from 

 that place, informs me that it was found very near the sur- 

 face, in digging the foundation of a cottage, in the neigh- 

 bourhood of a hill composed o'i Jlnty-slate ; and that he 

 has seen it adhering to a fragment of rock of that descrip- 

 tion : but it has occurred principally detached in the soil, 

 in the form of spherical nodules irregularly grouped toge- 

 ther, and of various sizes, the largest being about three- 

 fourths of an inch in diameter. These nodules are coaled 

 externally with a yellowish-brown earthy crust, and within 

 are of a crystalline structure ; resembling in their appear- 

 ance and properties the original IVaveUiteXxom Devonshire, 

 described by Mr. Davy, from which indeed, some of the 

 specimens from the county of Cork can scarcely be distin- 

 guished. 



The most distinct and purest specimens of this mineral 

 from the last mentioned pl^cc, that 1 have seen, exhibit 

 the following characters, viz. — 



The globules are formed of crystalline spiculse radiating 

 fro.n a coiTimon centre ; but the surfaces of these are 

 seldom perfectly plane, and their figure when separated 

 is not distinctly to be discerned. The exterior of the 

 nodules, is composed of the terminations of the cry- 

 stalline shoots, which are dihedral and obtuse-angled ; 

 the curvature of their surfaces, however, did not admit 

 of their being accurately measured. 

 The spiculae are nearly transparent and without colour, 

 or of H very light shade of yellovvi;^h green. The lustre 

 of their surface is strongly splendent, and glassy, in- 

 clining to that of silk : 

 The cross fracture of the spiculae seems to be fiat con- 



choidal, with a splendent lustre. 

 This substance scraiches glass ; but it is so easily broken 



down as to render difficult the trial of its hardness. 

 The nodules are very easily divided in the direction of 



the rays : the spicnlse are extremely brittle. 

 The specific gravity of a portion, which was very pure, 

 and about twenty grains in weight, was 2-34 . 



* Mineralr.gy of Scottish Ides, 410. i p. 81. 



Before 



