534 Palache and Warren — Chemical Composition and 



connection* with the riebeckite granite at Montorfano, N. 

 Italy. It forms there thin hexagonal crystals several milli- 

 meters long, generally embedded in a chloritic mass which is 

 encrusted with stilbite and chabazite, and is associated with 

 tluorite, pyrite and quartz. G. Tschernikf also describes the 

 mineral from a Manchurian locality where it occurred in an 

 erratic granite bowlder rich in pyrite and with accessory tluo- 

 rite and zircon. He gives chemical analyses of three differ- 

 ent phases of the mineral as found there, with an elaborate 

 discussion of the same. 



It thus appears quite certain that parisite, or the closely 

 related mineral synchisite and cordylite, are characteristic 

 pneumatolitic minerals of the riebechite-aegirite rocks. 



The parisite to be described in the present article, as well 

 as the other minerals, occurs in one part or another of the 

 pegmatite-pipes of the Quincy granite located in the quarry 

 of Fallon Brothers and the Ballou quarry, North Common 

 Hill, Quincy, Mass. The granite, as is well known, is a rie- 

 beckite-aegirite-bearing rock high in silica, ferrous and ferric 

 oxides and the alkalies, but very low in lime and magnesia. 

 The feldspar is almost wholly a microcline-microperthite. 

 These pegmatites have been described in a preliminary way in 

 a short article which appeared in this Journal in November, 

 1909, and are also described in considerable detail in a paper 

 which will appear shortly in the proceedings of the American 

 Academy of Arts and Sciences. The last paper will contain 

 also a somewhat fuller description of the minerals of the peg- 

 matites (with the exception of the parisite) than will be given 

 here, and to this paper the reader is referred for further details. 



In the larger Fallon-quarry pegmatite the parisite is rela- 

 tively abundant in all parts where open spaces are present, 

 implanted on the surfaces of the microcline and aegirite crys- 

 tals. It was particularly abundant along the immediate lining 

 (consisting almost entirely of microcline and aegirite crystals) 

 of the large central pocket, and was found to some extent on 

 the surfaces of the many pegmatite fragments found in the 

 open space of the pocket. In a similar pipe, but without any 

 central pocket, in the nearby Ballou quarry, it has been 

 observed only as grains in the massive rock. It may also be 

 noted that occasional grains have been identified in the Quincy 

 granite in other parts of the area, but seem to be confined to such 

 parts of the granite as show other undoubted evidences of 

 pneumatolitic activity. In one instance it has been noted in 

 close association with minute crystallizations of astrophyllite4 



*Rend. Ace. Line, xiv, 2, 88, 1905. 



f Verh. Mm. Ges. St. Petersburg, xliv, 1906, pp. 507-545. Reviewed in N. 

 Jahrb. f. Min., etc., Band ii, p. 386, 1909. 



:fOn the Occurrence of Astrophyllite in the Quincy Granite, see Pirsson, 

 this Journal, xxix, p. 215, March, 1910. 



