, , Felspar. 287 ihe cryftals are longitudinally ftreaked, middle fized, large, and very large. Lullre of th.. furface is moltly fplendent, approach es to pearly. I-uftre of the principal fra&ure is fplendent; the crofs fraflure Ihining, and intermediate between vi treous and pearly. > The principal fra&ure is perfectly fpecularly fo- Hated, with a two-fold rectangularly interfering cleavage ; crofs fraChire fmall and imperfectly con- clioidal. fragments rhomboidal. _ Has a tendency to thick and ftraight lamellar dif- tIn ct concretions. Semitranfparent and tranflucent. Hard. Brittle. T-afily frangible. Hot particularly heavy. gravity—From 2,500 to 2,60c, Struve 2,561*. Chemical Characters. a Before the blow pipe melts without addition inta glafs. Constituent
