apophyllite

[In Ger. apophyllit; Gr. (1) από ( apo ) = from; (2) φύλλον (phullon) = a leaf; and (3) suff. -ite ( Min. ) (q.v.). Apophylite was so called by Haüy from the tendency to exfoliate.] A tetragonal mineral, called also Ichthyophthalmite, cla ed by Dana as the type of an Apophyllite group of Uni silicates. The hardne is 4-5 to 5; the sp. gr. 2-3 to 24; the lustre of the face of the crystal terminating the low prism, pearly; that of the sides, vitreous. Colour: white or grayish; occasionally with greenish, yellowish, rose-red, or flesh-red tint. It is generally transparent; is brittle, and has feeble double refraction. It is a "hydrated calceo-pota ic silicate;" its composition being - silica, 51-60 to 52-69; lime, 24.71 to 25.86; pota a, 4.75 to 575; water, 15.73 to 16.73; and fluorine, 15-73 to 16.67. It occurs chiefly in amygdaloid, though occasionally in granite and gnei . It is found at Ratho, near Edinburgh, and in Fife, Dumb art on, and Inverne -shires. It occurs also on the continent of Europe; near Poonah and Ahmednuggur, in India; in Siberia; in Nova Scotia, and other localities in America; in Australia, and elsewhere. Dana subdivides it into Ordinary (1) Oxhaverite; (2) Te elite; (3) Leucocyclite; and places with it also Xylochlore.