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MALACONE AND OERSTEDITE. 649 bottle-green glass. Is decomposed by hydrochloric and nitric acids, leaving the silica in pearly scales. Analysis by Soltmann: —silica 37-40, alumina 11'60, red oxide of iron 27-06, protoxide of iron 12-43, magnesia and lime 0'60, potash 9-20, water 0'60. Is said to have been found at Persberg in Wermland. MARGARODITE.—A mineral resembling mica, from the Greiner. g = 2-87. Analysis by Schafhautl: — silica 47 05, alumina 34 90, red oxide of iron i - 60, magnesia i'9o, potash 7-90' soda 4'07, water 1’45. ’ MUEOMONTITE.—Lustre vitreous. Slightly translucent. Black. Streak grey. 11 = 7. g = 4-265. Glows before the blowpipe. Slightly fusible on the edges. Is decomposed by acids, leaving a jelly of silica. Analysis by Kerndt:—silica 31-09, alumina 2'24, glucine 5-52, yttria 37'14, protoxide of iron 1123, protoxide of manganese 0 91, protoxide of cerium 6 54, oxide of lanthanium 3'64, magnesia 0*42, lime 0'7l, soda 0'65,’ potash 0-17, water and loss 0'85. Is found in small grains with bodenite in oligoklas at Boden near Marienberg in Saxony. MALACONE and OEESTEDITE are names given to two minerals having the form of zircon. No cleavage has been observed in either of them. Perhaps they are zircon in dif ferent stages of decomposition, or of metasomatic change. These substances have been described as follows :—Malacone.— Eracture conchoidal. Lustre vitreous. Internally milk-w r hite, inclining to grey. 11 = 0-0. G = 3'903...3-913. Heated quickly to redness phosphoresces slightly, after wdiich g = 4-22. In fusible before the blowpipe. In fine powder slightly soluble in borax and salt of phosphorus. In fine powder decomposed by digestion in heated sulphuric acid. Analysis by Scheerer: silica 31-31, zirconia 63-40, red oxide of iron 0'4l, yttria 0 34 limo 0'39, magnesia O'll, water 3-03. Is found at Ilitteroe in Norway. Ocrstedite.—Translucent. Lustre adamantine in clining to vitreous. Yellowish-brown. 11 = 5-5. G _ 3.^9 In the matrass yields water. Infusible before the blowpipe' With borax melts with difficulty into a colourless glass. Ana lysis by Eorclinmmersilica 19-71, titanic acid and zirconia 68’98 magnesia 2-06, lime 2'6l, protoxide of iron ri4, water 5-53. Is found at Arendal in Norway with uralite and sphene. There are some pale yellowish-brown pyramidal crystals from Brazil in Mr. Brooke’s cabinet, having the form and measurement of zircon and the appearance of being either partially decomposed or pseudo- morphous. They formed part of the collection sent by Captain Lyon to this country, and have not, that we are aware of, been analyzed. ’ r f