SAPPHIRE D'EAU, or loixru, a mineral, called also diehroite and Cordierite, one of the anhydrous silicates of alumina; crystalline form, six or twelve-sided rhombic or hexagonal prisms, but often found in an amorphous condition. The color is of various shades of blue—deeper in the axial direction; yellowish-gray transversely; transparent to translucent, having much the appearance of glass. Hardness, 7 to 7.5; specific grav ity, 2.6 to 2.7.. The following is an analysis by Stromeyer of a specimen from Boden mais, Bavaria: Silica, 48.35; ahimina. 31.71; magnesia, 10.6; protoxide of manganese, 0.33; protoxide of iron, -8.32; water, 0.59 = 99.46. A specimen from Haddam, Conn., gave: Silica, 49.62; alumina, 28.72; magnesia, 8.64; protoxide of manganese, 1.51; Protoxide of iron, 11,58; lime, 0.23 = 109.3. A specimen from Unity, Me., ocording to Jackson, gave: Silica, 48.15; alumina, 32.5; magnesia, 10.14; protoxide of manganese, 0.28; protoxide of iron, 7.92; water, 0.5 = 99.49. Iolite fuses slowly on the edges in the blow-pipe flame to a blue transparent glass; with borax it forms a clear bead. When in fine powder it is partially dissolved in concentrated mineral acids. It occurs at Bodcnmais in perfect crystals II in. thick, and this variety has been called pelione, from its smoky appearance. It occurs in quartz at Ujordlersoak in Greenland; in granite at cape de Gata, Spain; at Arendal in Norway; and at Tunaberg in Sweden. In Ceylon
there is it transparent variety occurring in small, rolled 'misses of an intense blue color, which is particularly the sapphire cream of the jewelers. Iolite occurs at Haddam, Conn., associated with garnet and anthrophyllite in gneiss, and in various other parts of Connecticut and Massachusetts, and at Richmond, N. H., in talcose rock Iolite is sometimes used as an ornamental stone, and, when cut, has a very fine play of colors, which vary, as above stated, when viewed in different directions. The word iOlito means violet stone. It is called diehroite from its dicliroism (q v.), and Cordierite after the geologist, M. Cordier. Iolite becomes soon altered on exposure to air and moisture. The change may he caused by simple hydration, as in fahlunite, or the removal of part of the protoxide bases by carbonic acid, or by the action of water containing alkaline carbonates, forming pinite and mica. There are several other altered forms, as giganto life, aspasiolite, praseolite, weissite; pyrargellite, liebenerite, iberite, and Huronite, the latter from Canada, near lake Huron, considered analogous top/du/lite by T. Sterry Hunt.