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ANDALUSITE. 285 faces r, c, r > , and make angles of 46° 13 '5 with a normal to c. Pearl-grey, flesh-red, peaeh-blossom-red... violet... reddish- hrown ; seldom green. In a variety from the Brazils rays transmitted through the crystal in planes parallel to a, b, c, and polarized in those planes, are oil-green, olive-green and red respectively. Streak white. H = To. G = 3'1...3‘2. Infusible before the blowpipe. Soluble with extreme diffi culty in borax, forming a clear glass. In powder becomes blue with solution of cobalt. Very slightly attacked by acids. AlSi, silica 37'62, alumina 62-48. Analyses of andalusite a from Herzogau by Bucholz, b of peach-blossom-red andalusite from Munzig in the Triebischthal, G = 3'152, by Kersten, c from Fahlun by Svanberg, d from Lisens by Bunsen, e from Lisens, G = 3-164, by A. Erdmann Silica .... Alumina . . lied oxide of iron Magnesia . . Lime .... a b C d e 36-5 37-61 37-65 40-17 39-99 60-6 60-01 69-87 68-02 68-60 4-0 1-49 1-87 — 0-72 0-40 0-38 (iifn. 0*51 0’83) 0-48 0-68 0-28 — Andalusite decomposes very readily, being frequently con verted into a stcatitic substance containing kyamte, or into a substance like kaolin, for which H = 3, G 2 70. In attached and imbedded crystals, in granite, gneiss, mica 8k Is'found near Toledo, in the Sierra Morena and in Aragon ; Lisens in the Tyrol, Arber near Bodenmais, Lahmerwmkel and Herzogau in Bavaria, Kaplitz and Albenreuth near Iglati m Bohemia, Goldenstcin and Wmkelsdorf in Moravia, Landeck and Prciwaldau in Silesia, Braunsdorf and Penig in Saxony, at Eorez in France, near Schaitansk m Siberia, m the alluvium of Gupiara in Minas Novas in the Brazils, at Botrifney in Banffshire in gneiss, in mica slate at Killmey m Ireland, Lich field in Connecticut, and Westford in Massachusetts. FIG. 308. Chiastolite appears to be a variety of andalusite having prisms of a darker sub stance in the centre, and sometimes m each angle, connected by thin plates of the same. The dark portions are cither the slate in which the crystals are imbedded, or discolorations produced by carbona ceous matter, which disappear on igniting the crystal, it = 5'0 ...6-6. G = 2'9. ..2-06. : j ; i
