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ILMEJTITE. 241 0 P 2 r S t 19-48 19-91 13-90 27-23 29-27 29-04 0-32 0-33 0-86 0-96 0-60 0-49 0-73 0-68 1-10 2-30 1-22 1-94 — — 0-44 0-12 0-33 — 3-64 — Mn 0-21 T, «e 0-68 0-80 1-17 1-88 0-31 1-65 0-07 Protoxide of iron Lime .... Magnesia . . . Oxide of chrome. Oxide of tin . . Silica .... It is supposed by II. Eose and Scheerer that the titanic acid (it) results from the combination, during the analysis, of the blue oxide of titanium (®) with part of the oxygen of the red oxide of iron (£*), converting a portion of it into protoxide of iron (r e ). According to these views, the true constitution of the different varieties of ilmenite would be as follows:— a b c i d e m f g *1 . 63"69 47-01 42'69 40'89 38'25 20'13 14'01 13'39 8'68 • 40-31 62-96 67-41 56'37 ei‘75 79‘87 83’83 86'61 81‘42 In attached and imbedded crystals, granular and lamellar Masses, disseminated and in angular or rounded grains. It is found with dolomite in talc at G-astein in Salzburg (orn', oersn'), Lappach in the Tyrol, in miascite on Lake Ilmen iiear Miask in the Ural (ores, oresn), in Norway at Tvedestrand m garnet (ora, orea), Eriedriehswiirn in zircon-syenite, Eger- s und, Banile near Krageroe (oransm), Arendal in beds of mag netite, Bodenmais in Bavaria, Bourg d’Oisans in Dauphine (crichtonite, the combinations containing the form p) in drusy cavities with quartz, albito, anatase, brookite, Spessart near Asehaffenburg, with rutile at Malonitz near Klattau in Bo hemia, St. Gotthardt, in isolated grains in alluvium at Iserwiese the Eicscngebirge, in the gold stream-works at Ohlapian 111 Transylvania, in the United States at Washington, Lichfield, iVesterley and Goshen in Massachusetts, Essex in New York. I bo combination o^ersna occurs in crystals from Hamburg in ■New Jersey, in Mr. Brooke’s collection. According to Mohs rr' = 94° T. The values of rr' obtained by Breithaupt for varieties from different localities are as fol lows :— Miask .... 94° 17' Tavetschthal . . 93° 62-4' fi’Oisans ... 93 63‘6 Tvedestrand . . 93 50 Mohsite is perhaps ilmenite. Bhombohedral. o ill, a oil. Tbc value of \^o in mohsite approaches to that of ipo in hema- tite. If we suppose \p be 664, a will be 722, and t 10 1 l.
