I'llHHMTK 171 



Dif, Distinguished from beryl, green quartz, and chalce- 

 dony by fusing before the blowpipe, and from the zeolites by 

 its superior hardness. The ordinary broken appearance of 

 its crystals is quite characteristic. 



Obs. Found in trap, gneiss, and granite. 



Occurs in the trap of Farmingto n. and Woodbury, Ct., 

 West Springfield, Mass., and Patterson and Bergen Hill, N. 

 J. ; in gneiss at Bellows Falls, Vt. ; in syenite at Charlestown, 

 Mass. ; and very abundant, forming a large vein, in the cop- 

 per region of Lake Superior, three miles south of Cat har- 

 bor, and elsewhere. v .-' ,-i b Q . ' 



The Fassa valley in the Tyrol, St. Crystophe in Dauphi- 

 ny, and the Salisbury Crag, near Edinburgh, are some of the 

 foreign localities. 



Uses. Prehnite receives a handsome polish and is some- 

 times used for inlaid work. In China it is polished for orna- 

 ments, and large slabs have been cut from masses brought 

 from there. 



Epistilbite. A hydrous silicate of alumina and lime. Occurs in 

 thin rhombic prisms, of a white color, with a perfect pearly cleavage 

 like stilbite. H=3| — 4. Gr=2*25. Before the blowpipe froihs and 

 forms a vesicular enamel. Does not gelatinize. From Iceland and 

 Hindostan, and sparingly at Bergen Hill, N. J. 



Antrimolite. A stalactitic zeolite, from Antrim, Ireland. 



Edinglonite. In small right square prisms, with lateral cleavage. 

 Nearly colorless ; luster vitreous. H=4 — 45. Gr=2*7 — 2*75. Oc- 

 curs with thomsonite at Dumbartonshire. 



Carpholite. In minute radiated and stellate tufts of a straw yellow 

 color, and silky luster. From the tin mines of Schlackenwald, Aus- 

 tria, with fluor. 



Chlnrastrolite. Light bluish-green, with a radiated structure, and 

 somewhat like prehnite. H=55 — 6. Gr=3'l8. Occurs on the shores 

 of Isle Royale, Lake Superior. Named frotn the Greek chloros, green, 

 astron, star, litlios, stone. 



Faujasite. A hydrous silicate of alumina, lime and soda. Crystals 

 square octahedrons. A : A=lli° 30' and 105° 30'. Scratches glass. 

 Occurs with augite, at Kaiserstuhl. 



Glottalite. A hydrous silicate of alumina and lime, said to be mon- 

 ometric in crystallization. Ii=3"5. Gr=2l8. Color white. Luster 

 vitreous. Translucent. From Scotland. 



Margarite, a mineral resembling a pearly mica, but hardly elastic 

 and Eupkyllite, are hydrous species, somewhat related both to chlorite 

 and to mica. They are mentioned on page 193. Emerylite is iden- 

 tical with margarite j diphanite may also be the same species. 



Where does prehnite occur 1 How is it distinguished from the zeo- 

 lites and quartz ? What are its uses 1 



