128 



The specimen here figured came from Kirkleston, 8 

 miles west of Edinburgh, and seems always to present the 

 same crystallization more or less compressed. The crystals 

 vary in transparency from translucid to nearly opaque white, 

 and are often of a pale red, sometimes of a dull salmon 

 colour. I was favoured with some of these from Calton Hill 

 near Edinburgh by Mr. Neale. The fracture is often very 

 confused, and somewhat like quartz after being dropt red hot 

 into water. I however had the good luck to find one, among 

 many specimens sent me by Mr, J. Murray of Edinburgh, 

 with the proper cubic fracture, which leaves me no room to 

 doubt that the crystals here figured belong to the cubic zeo- 

 lite of Brochant. The Dumbarton crystals that I have seen 

 are also the same species. Mr. J. Murray, who sent them 

 to me, is of the same opinion. The rock however in 

 which they are found differs, as well as the manner of 

 their immersion. Those figured are in grunstein* of Wer- 

 ner, (see Kirwan 1. 353.) and situated in hollow cracks or 

 fissures. Those of Tab. 58. are lying in hollows or moulds, 

 and are apparently the residuum of the substance which 

 previously filled the space. Mr. Kirwan speaks of Vesuvian 

 garnets from the size of a pin's head to that of an inch. We 

 have some which differ in appearance only by a dirtier hue, 

 the gangue often partly sticking about them, which is of a 

 muddy brown : the mould or holes they were in are some 

 smooth and some rough. This is the amphigene of Haiiy^ 

 and might be confounded with the analcime : but the latter 



* Hornblende and felspar. 



