CniLISTIANITE. 877 ep em qp xp yp ip op tip rp 42 38 43 10 34 48 51 33 81 31 41 14 68 10 85 7 45 14 FIG. 391. 07)1 uni vp vm top tom *p pml xml 64° 40' 67 15 88 4 38 0 81 23 38 38 64 22 110 14 04 41 yml 34° 43' qml 81 26 imt 22 32 FIG. 390. mf FIG. 393. m Combinations, pthoney.uxqri, xsoypeitlm, xsoyuvwnepiltfzm. Twins. Twin-face m (fig. 392). pd — — 8° 24'. Cleavage. P, m, perfect. Fracture conchoidal. Transparent...translucent. Lustre vitreous, on the cleavage faces pearly. Colourless, white. Streak white. Brittle, it = 6'0. g = 2’066...2703. Melts with difficulty before the blowpipe into a blebby glass. 'With soda forms an opaque white glass. Is completely decom posed by hydrochloric acid, leaving silica in powder. CaSi + AlSi, silica 4372, alumina 36'40, lime 19'88. Part of the lime is usually replaced by magnesia, potash and soda. Analyses of christianite a from Monte Somma by G-. Eose, c from Monte Somma by Abieh, d from tlie lava of Java by llciuwardt, e from Sclfjall near Lamba in Iceland (g = 2 70),
