179 



TAB. CXCIII. 



SILEX Prehnites. 

 Prehnite* 



Class 2. Earths. Order 1. Homogeneous. 

 Gen. 4. Silex. Spec. Prehnite. 



Syn. Prehnite. Haiiy, 3. 167. Kinv. 1. 274. 



Schorl en gerbes de Schreiber, Prehnit. Erri* 



merl 1. 192. 

 Zeolithe verdatre. De Born, 1. 203. 

 Chrysolite du Cap. De Lisle, 2. 275. 



x rehnite was said to have been first discovered by co- 

 lonel Prehn, who brought it from the Cape of Good Hope ; 

 Haiiy, however, says that citizen Rochon was beforehand 

 with him. — It is now found in many parts of Scotland. 

 The present specimen comes from Dumbarton, and, when 

 examined, exhibits a curious arrangement of crystals, in 

 groups, forming hemisphserically, and showing faces which 

 are the edges of tabular crystals arranged somewhat in seg- 

 ments of circles, having the larger crystals in the centre ; 

 see the left-hand lower figure. These crystals seem to 

 betray signs of eight faces besides the two broader ones, 

 like the right-hand figures . The nucleus we could not posi- 

 tively determine; it seems, however, to be a nearly rectan- 

 gular table, as expressed by the dotted lines : thus the cor- 

 ners are as it were unfinished, or truncated. The upper 

 figure is of the natural size ; the loiver one, for the sake of 



VOL. IJ. P 



