PREHNITE. 205 The cryftals are either fingle, manipularly, or wulzf ormig, aggregated *. In this latter kind of aggre gation the lateral planes are fo grown together that °nly the terminal planes are to be feen.. Sometimes the cryftals are a little convex in the Middle, owing to exfoliation. They are fmall and Middle- fized. Externally the cryftals are fmooth and fhining, in ternally fhining inclining to gliftening, and pearly. Erasure fometimes foliated with an imperfect Engle cleavage, alfo fometimes fmall fcopiformly di- Ver ging radiated. Eraginents indeterminately angular, and wedge- fltaped. ,,, • t he foliated, occurs in coarfe and fmall grained dif- htiQ: concretions; the radiated in wedge-lhaped prif- ttla dc diftinft concretions. h is tranflucent, but fometimes pafles into femi- hanfpareut and tranfparent. Hard f. Eafily frangible. Hot particularly heavy. Specific gravity—Prehnite of the Cape, 26,969, Hauy ; >94*) BriJJan; 2,9423, Kirvian Prehnite of France, 26 >°97, Hauy. I have not found a corrcfpondinij Emjlith term for the Ger- XTian nf.. / /'. * Tvwzfbrmig* t Scratches glafs flightly. Hauy. ' • ’ ‘ Chemical