330 Notice of Topaz and Phenakite. 



rived from the rhomboid, in addition to which also, it has the lus- 

 tre, transparency, and color of quartz. In chemical composition 

 however, it is more nearly related to the beryl, being a bisilicate of 

 glucina. 



My first knowledge of the American mineral which I take to 

 be Phenakite, was acquired about fourteen years ago, during a 

 visit to the tourmaline locality in Goshen, (on the farm of Mr. 

 Weeks, ) in company with Mr. Nuttall and the late Dr. Hunt of 

 Northampton. My first impression was, that it belonged to iolite,* 

 an opinion I afterwards changed in favor of the species beryl,f 

 under which name, I believe, it has generally passed in cabinets 

 ever since. | Prof Hitchcock, in his Report on the Geological 

 survey of Massachusetts, (p. 506, 1st edit.,) undoubtedly refers to 

 the same substance, when he says, " Beryls are frequently met 

 with in our granite, though in general they are not very delicate. 

 Perhaps the most so is a limpid, large beryl, occurring in Goshen, 

 along with spodumene, &c. It is rare to find it distinctly crys- 

 tallized, and it is full of fissures. Sometimes it is of a light rose 

 color. (Nos. 1525 to 1528.)" Nor can there be the slightest ques- 

 tion that the " rose-colored emerald" alluded to by Col. Gibbs,<^ 

 as furnished him from Goshen, pertains to the species under con- 

 sideration. 



It occurs in considerable plenty, distributed through the granite 

 in small crystalline masses, from the size of a pea to a hazel-nut, 

 generally oval in form, and rarely in short hexagonal prisms, some 

 of which present one face or more of the primary rhomboid, in 

 the absence of their alternate angles. Other masses are rounded, 

 and ofier occasionally a few roughened faces, which probably 

 pertain to the primary or to a secondary rhomboid. The prevail- 

 ing color is a pale bluish white, though sometimes a faint rose- 

 colored tinge is observable, especially in the well-formed hexago- 

 nal prisms. Lustre vitreous ; transparent to translucent only on 

 the edges. When perfectly transparent, it is a very handsome 

 gem, much resembling the euclase, and like that mineral, is filled 

 with fissures, and very fragile, though wanting in its brilliant 

 cleavage. Hardness = 7.5, being barely adequate to scratch quartz. 



* Boston Journal, vol. 13, p. 395. t Idem, p. 607. 



\ It should be remarked moreover, that it vi'as referred by some collectors for a 

 time, to topaz. 



§ Vol. I, p. 351 of this Journal. 



