538 PROCEEDINGS OF THE ACADEMY OF [Oct., 



SOME BERKS COUNTY MINERALS. 

 BY EDGAR F. SMITH. 



Ten years ago, the late Ex-Congressman D. B. Brunner and Dr. 

 Schoenfeld, of Reading, Pa., placed in my hands a number of minerals 

 which they gathered from a railroad cut east of Reading. Consider- 

 able blasting had been done and a great deal of rock material had been 

 removed. It was upon pieces of this rock and in its crevices that 

 they obtained the minerals which I was to examine at my leisure 

 and analyze if I cared so to do. At intervals these minerals have 

 been submitted for study in the laboratory of the University of 

 Pennsylvania, with results that have been more or less interesting. 



Laumoxtite. — The color was chalk}*-white and the lustre vitreous 

 and pearly. Before the blow-pipe it fused quite readily to a white 

 enamel. It was gelatinized when digested with hydrochloric acid. 

 The specific gravity of the sample taken for analysis was found to be 

 2.253. As a result of analysis it showed 14.12 per cent, loss upon 

 ignition; 11.89 per cent. CaO; 22.2 per cent. Al,( ) 3 , and 52.12 per 

 cent. Si< > 2 . 



Apophyllitk. — The crystals of the specimen examined were color- 

 less to white, with a vitreous lustre and basal cleavage. When heated 

 in a closed tube it exfoliated, became milk-white in color, and gave 

 forth much water and showed a slight acid reaction. Before a blow- 

 pipe it fused to a plebby glass. It was decomposed by hydrochloric 

 acid with the separation of silica, but it was not distinctly gelatinized. 

 Its specific gravity was found to be 2,399. On analysis it showed : 



Si0 2 52. 03 per cent. 



A1,0 3 0.28 



Fe,0 3 Trace 



Cat) 25.11 



Na 2 0.71 



KgO 5.13 



Ign 17.43 



Another specimen of crystals distributed over prehnite gave a spe- 

 cific gravity of 2.37, and on analysis showed : 



SiO^ 51.95 per cent. 



A1 2 3 + Fe 2 3 2.94 



CaO 23.68 



K 2 4.47 



Na,0 0.34 



MgO 0.36 



Ign 15.81 " 



