74 Scientific Notices — Mineralogy. [July, 



number of this Journal, page 390, we have noticed the dis- 

 covery of green felspar at Beverly in this state. The speci- 

 mens first found were met with in a stone wall ; it was ascer- 

 tained that the materials for the construction of the wall were 

 taken from the common, or parade ground of Beverly, many 

 years ago. Application was made to the proper authorities for 

 permission to open the ground and make a thorough examina- 

 tion. The result of this undertaking has been highly satisfac- 

 tory. The green felspar has been found in narrow veins tra- 

 versing sienite, accompanied with crystals of zircon, and some 

 other substances, the nature of which has not as yet been satis- 

 factorily determined. 



The crystals of zircon have an amber-brown colour, a resin- 

 ous and oily lustre, with a fracture somewhat conchoidal and 

 foliated. The cleavages, in some of the crystals, are tolerably 

 distinct and indicate the octohedral primitive form. A few per- 

 fect octohedral crystals have been found. 



The largest crystal in my possession, weighs 30 grains -^ths, 

 and its specific gravity is 4*06 ; it is a four-sided prism termi- 

 nated by a four-sided pyramid ; the terminal planes being set 

 upon the lateral edges of the prism. 



With the reflective goniometer I find the angle of inclination 

 130° 12'. The angles scratch rock crystal. 



The hornblend and felspar which accompany these interest- 

 ing substances, very much resemble those of the zircon sienite 

 cf Von Buch, with a specimen of which in my collection I have 

 carefully compared it. The structure of this rock, and its geo- 

 logical connexions, are highly interesting. The following is 

 Von Buch's description of the Norway zircon sienite. It is 

 strongly distinguished from every porphyry by the magnificent, 

 coarse granular, and sometimes large granular felspar, partly of 

 a pearl-grey, and partly of a red colour, which always strongly 

 characterises the blocks by its high degree of lustre. It is 

 equally distinct from granite, sienite, or other similar granular 

 stones, by the preponderance of the felspar. All the other ingre- 

 dients seem to be sunk in this as a basis, and they often appear 

 only occasionally ; but hornblend is never wanting, and this 

 hornblend is generally pretty characteristic and distinct ; long 

 black crystals, which possess a double foliated fracture by way 

 of discrimination from mica — folia of mica also make their ap- 

 pearance but very rarely ; and quartz shows itself in small 

 grains, so as not to be altogether missed. It appears, in gene- 

 ral, accidentally in the composition, and we search through 

 whole hills without finding it again. Wherever the grains of 

 the felspar meet, there remains almost always a small angular 

 cavity into which crystals project. Among these, are the crys- 

 tals of zircon, which give name to the rock. Epidote is asso- 

 ciated with them in fine needles. 



