114 RE-EXAMINATION OF AMERICAN MINERALS. 



5. Kerolite of Unionville, Pa., a hydrated silicate of 



Alumina. 



Associated with euphyllite and unionite, there occurs a 

 peculiar amorphous mineral, which has been circulated among 

 some of our American mineralogists under the name of kerolite. 

 In our examinations of the minerals from this locality we 

 thought it of sufficient importance to ascertain its chemical 

 composition. 



In physical characters it resembles kerolite ; hardness 2.25 ; 

 specific gravity 2.22 ; color yellowish-white ; brittle ; crumbles 

 to pieces when thrown in water. Analysis gave 



Si XI Mg Mn JSTa&K H 



44.50 25.00 7.75 trace trace 22.39=99.64 



Of the water 1.04 per cent, was lost by twenty-four hours' 

 desiccation over sulphuric acid, 8.81 per cent, by heating to 

 212°, and the remainder at a red heat. 



In chemical composition it is near halloysite. It is an imper- 

 fectly formed mineral, and consequently is not homogeneous ; 

 it passes into euphyllite and feldspar. 



6. EOWENITE, IDENTICAL WITH SERPENTINE. 



This mineral occurs at Smithfield, E. I., and was described 

 by Bowen* as a variety of nephrite. His analysis gave 



Si 



Mg 



Ca 



Fe 



XI 



Mn 



H 



44.69 



34.63 



4.25 



1.75 



0.56 



trace 



13.42 



This composition differed so much from nephrite, and cor- 

 responded so closely to the formula 2(MgCa) 2 Si-f 3H, that Pro- 

 fessor Dana felt himself justified in noticing it as a distinct 

 species.f 



The following are the physical characters of the mineral : 

 Hardness 5 (it will scratch glass if rubbed with a little force 

 against its surface; it first gives way, but ultimately scratches 

 the glass); specific gravity 2.57; color, in large masses, bright 

 apple-green; highly translucent; structure granular, and ex- 

 ceedingly tough. We give analyses of three specimens. No. 



* Amer. Jour. Science and Arts, 1st series, vi, 346. 

 t Dana's Mineralogy, 3d edition, p. 265. 



