MAEGAEITE. 393 n 0 P i r s t 48-92 47-01 42’97 48-65 46-62 61-70 20'80 19-03 20-35 20-69 17-67 21-81 26-76 — 14-34 14-18 — 4-78 — 4'30 6-59 — 0-83 — — 1'29 1-63 — 1-24 1-96 — 0-11 0-14 — (re 14-57 6"80) 0‘40 — — — — 0-63 0-44 0-24 10-96 9'62 10-02 8-60 9-09 10-29 2-77 4-33 1'60 2-41 1-27 1-27 2’23 — 1’41 0-71 0-39 116 10-44 1-43 6’3S 8-16 7-47 7-12 1-31 0-40 0’21 P 0-13 0-16 — — 1-53 0-22 — — icipally in granite, taking the pla ce of mica, Silica . . Alumina . U«d ox. iron Ox. man. . Protox. man. Lime Magnesia . Potash . . Lithia . Soda . . Pluorine . Chlorine . Loss ign. . Is found at Eozona near Hradisko in Moravia, at Chursdorf near Penig in Saxony, in Uto, near Mursinsk in the Ural, at Paris in Maine, Middletown in Connecticut, in the tin-mines of Bohemia, Saxony and Cornwall. 220. MAEGAEITE.—Margarite; Phillips, Beudant. He- miprismatischer Perl-Glimmer ; Mohs. Margarit; Ilausmann, Haidinger. Oblique. In thin six-sided prisms forming thin crystalline laminae. Cleavage parallel to the base of the prism, very perfect. Semi transparent... translucent. Lustre, the cleavage faces pearly; the other faces vitreous., Reddish-white, greyish-white, pearl- Rnoy. Streak white. Rather brittle. In thin leaves slightly elastic. II = 3'5...4’5. G = 30...3'1. Intumesces and melts before the blowpipe. Is attacked by acids. Analysis of margarite made in the Gottingen laboratory:— Silica . 83-60 Alumina . 68-00 Lime 7'60 Protoxide of iron . . . 0-42 Magnesia 0-06 Protoxide of manganese . . 0'03 Is found at Sterzing in the Tyrol w’ith chlorite. s 5