192 IRON- ALUM. 



Not soluble in any acid. 



Locality^ The Ural, with Native Platinum, 

 Titanic Iron, Tridosmine, and Hyacini h, often 

 filling up interstices between the separate 

 grains in large masses of platinum. 



Brit. Mus , Case 2. 



Iron-alum. See Halotbichite. 



Iron-apatite. See Zwieselite. 



Iron-chrysolite, See Fayalite. 



Ikon-earth. Occurs as a black pulve- 

 rulent mass, which attaches itself closely to 

 anything on which it is rubbed, and is 

 strongly attracted by the magnet. S.G. 

 about 3-8. 



Comp, (Fe Mn) Pe, or Magnetic Iron- 

 ore, in which about half the ])rotoxide of 

 iron is replaced by protoxide of manganese, 

 with which it is amorphous. 

 Analysis, b}^ Genth : 

 Peroxide of iron . . . 65*68 

 Protoxide of iron . . 141)9 



Protoxide of manganese . 16 25 

 Oxide of copper . . . 0-09 

 Oxides of cobalt . . . traces 



Water trace 



Gold-sand, &c. . , .2-34 



98-45 



Locality. The Alte Birke Mine, in the 

 neighbourhood of Siegen, in Prussia, where 

 a vein of Spathic Iron is broken through by 

 basalt, and partlv converted into Magnetic 

 Iron-ore. (Gmelin.) 



Iron- flint, Jameson. See Ferruginous 

 Quartz. 



Iron- foam. See Micaceous Iron-ore. 



Iron-glance, Jameson. See Specular 

 Iron. 



Iron Mica, Jameson. I\Iicaceous Iron-ore. 

 Sometimes found in small and extremely 

 thin six-sided plates, wdiich are translucent 

 and display a darlc red colour by trans- 

 mitted light. The principal locality is Cattas 

 Altas, in the Brazils. It generally, how- 

 ever, occurs massive, and constitutes a valu- 

 able ore of iron. 



Brit. Mus., Case 15. 



Iron Natrolite. A variety of Natrolite 

 in which one-fourth of the alumina is re- 

 placed by peroxide of iron. It occurs in 

 dull green opaque prismatic crystals and 

 semi-crystalline plates, Avith the Brevicite 

 of Brevig, in Norway. H. 5. S.G. 2'353. 



Analysis, by C. Bergemann : 



Silica 46-54 



Alumina .... 18-94 

 Peroxide of iron . . . 7-49 

 Soda with a little potash . 14-04 



ISERINE. 



Protoxide of iron . . .2 40 

 Protoxide of manganese . 0-55 

 Water 9-37 



99-33 



Iron-nickel Pyrites. See Sulphide 

 OF Iron and Nickel. 



Iron Ochre, or Ochreous Iron-ore. 

 See Hematite and Limonite. 



31. P. G. Principal Floor, Wall-cases 

 38 (E. Indies) 49, No. 355. 



Iron Pyrites, Phillips. See Pyrites. 



Iron Roses. (Eisenrosen.) See Basano- 



MELANE. 



Iron Rutile. See Gothite. 



Ironshot Copper Green, Jameson. An 

 impure Chrysocolla. When the colour in- 

 clines to brown the mineral is impure. 



Iron Sinter, Allan. See Pittictte, 



Iron Spar. An anhydrous carbonate of 

 protoxide of iron. It occurs in rhombohe- 

 dral forms, and is isomorphous with Calc- 

 spar. See Chalybite. 



Iron Vitriol, Jameson. See Copperas. 



ISERIN, Werner ; Iserine, Jameson, Bro- 

 chant, Phillips. Cubical : in octahedrons, 

 with the faces of the crystals uneven and 

 rounded. Occurs in small obtuse angular 

 grains, and in rolled pieces, with a some- 

 Avhat rough surface, or in the form of black 

 sand in alluvium or in the beds of rivers ; 

 also massive and disseminated in basalt. 

 Colour iron - black. Lustre submetallic. 

 Opaque. Streak black. Brittle. Some grains 

 of this mineral are strongly magnetic, some 

 slightly, others not at all. H. 6 to 6-5. 

 S.G. 4-85 to 5-1. 



Comp. 3Fe Ti + Ee. 



Analysis, from Iserwiese, by Rammelsherg 

 (small grains, S.G. 4-745) : 



Titanic acid . . .41-64 



Oxide of iron . . . 26 82 

 Protoxide of iron . . . 26-85 

 Do. of manganese • . 1-00 



Magnesia .... 4*66 



100-97 



BB alone infusible. 



Localities. — British. The shore of the 

 Mersey, nearly opposite Liverpool, and at 

 Hunstanton, in Norfolk, mixed with Mag- 

 netite; near the mouth of the river Don, 

 Aberdeenshire ; in minute octahedrons 

 among boulders at Ballygrogan, Mull of Can- 

 tyre. In the trap rocks of Arthur's Seat, near 

 Edinburgh ; on the shore of Loch Trista, 

 one of the Shetlands. — Foreign. Unkel, on 

 the Rhine, and on Etna, in "basalt; also in 



