277 



IRON. 



IRON. 



273 



rhomboid. Cleavage parallel to the primary planes, and perpendicular 

 to the axis in some varieties. Fracture uneven, couchoidal. Hardness 

 5'5 to 65 ; scratches phosphate of lime ; is scratched by quartz. 

 Specific gravity 5'0 to 525. Lustre metallic. Colour steel- and iron- 

 gray ; the surface frequently iridescent. Obeys the magnet slightly. 

 Streak red and reddish-brown. It is found in the island of Elba and 

 in many other parts of Europe. It also occurs in the lava of Auvergne 

 in France, and in that of Vesuvius. 



Gothife, Pyrosiderite occurs in very thin transparent crystalline 

 plates in the cavities of black Hematite. Colour brownish-red, by 

 reflection yellowish, in a strong light of a brilliant red. Lustre ada- 

 mantine. It occurs in England and in Germany. The former yielded 

 by analysis 



Peroxide of Iron 89 '2 



Water 10'8 



100 



Iron Froth consists of very thin brownish-red scaly particles, 

 which have a greasy feel, and stain the fingers. It is found plentifully 

 in Devonshire and Lancashire, and was ascertained by Dr. Henry to 

 be pure Peroxide of Iron. The massive varieties are amorphous ; 

 structure foliated. 



Red Ilematite occurs in globular and botryoidal masses. Structure 

 fibrous, radiating, opaque. Specific gravity 4'7 to 5. Lustre extern- 

 ally sometimes metallic, sometimes dull; internally, nearly dull. 

 Colour externally red ; grayish-red, Ac., internally, and streak red. It 

 occurs in large quantity at Ulverstoue in Lancashire, and in other 

 parts of Great Britain and Europe. According to D'Aubuisson it 

 consists of 



Peroxide of Iron 94 



Silica 2 



Lime . . .1 



Water 3 



100 



Brown Hematite; Hydrous Oiide of Iron; Hi-own Iron Ore, 

 occurs in attached crystals and massive prisms. Primary form aright 

 rhombic prism. Cleavage parallel to the short diagonal ; fracture 

 uncertain. Hardness 5'0 to 5'5. Specific gravity 3'93. Lustre ada- 

 mantine ; nearly opaque ; translucent Colour brown of various 

 shades. Streak yellowish-brown. Occurs in Cornwall. 



Massive varieties globular, reniform, and some of the varieties of 

 brown and yellow clay iron-stone. Stalactitic, structure fibrous, 

 or fibre-laminar. Sometimes occurs in pseudoinorphous crystals. It 

 occurs in most parts of the world Analysis by D'Aubuisson : 



Fibrous. Compact. 

 Peroxide of Iron . . . .82 81 



Water 14 1 



Oxide of Manganese .... 2 2 



Silica 1 2 



99 89 



Franltlinile is a mixture of the peroxide with oxide of zinc. 

 [FiiANKLiNrTE.] Ilmenite contains iron and titanium. [TITANIUM.] 



Carbonate of Iron ; Brown Spar ; Spathose Iron Ore. This occurs 

 in attached crystals and massive. Primary form a rhomboid. Cleav- 

 age parallel to the primary planes, distinct. Fracture imperfect 

 conchoidal. Hardness 3'5 to 4'5. Specific gravity 3'6 to 3'829. 

 Transparent, translucent, opaque; lustre vitreous, inclining to pearly; 

 colour white, yellow, red, and brown of different shades. 



Massive varieties tabular, structure fibrous ; botryoidal and 

 globular (these being called Sphcerotidcrite), structure fibrous, diverg- 

 ing; amorphous, structure foliated, granular, compact. Found in 

 Cornwall, Scotland, and Ireland, and in other parts of Europe ; and 

 also in America. 



Before the blow-pipe it blackens and becomes magnetic, but does 

 not fuse ; in the reducing flame it colours borax bottle-green, and in 

 the oxidating yellow ; dissolves in acids with effervescence. Analysis, 

 by Beudant, of the hexahedral variety : 



Carbonic Acid 38 72 



Protoxide of Iron 59'97 



Oxide of Manganese 0'39 



Lime 0'92 



100 



Clay Iron-Stone, or Argillaceous Iron-Ore, consists essentially of 

 carbonate of iron mixed with various proportions of earthy matter ; on 

 an average carbonate of iron forms about one-third of the abundant 

 clay iron-stone of England, Wales, and Scotland. It occurs in beds 

 and in coal deposits ; it is found sometimes in globular masses, and 

 also columnar. 



Thoinaite is a carbonate of iron from the Siebengebirge. Junkerite 

 is common spathic iron. Mesitinc Spar is a carbonate of iron and 

 manganese ; so also is Oligon Spar. 



Sulphur and Iron exist in combination in enormous quantities ; the 

 compound.! which it forms are called Magnetic Iron Pyrites, Iron 

 fjfrtta, mid White Iron Pyrita. 



Mmjnelic Iron Pyrites, Protoiulphuret of Iron, occurs in imbedded 

 hexagonal crystals and massive. Primary form a rhomboid. Cleavage 

 parallel to all the planed, of a regular hexagonal prism; fracture 

 uneven, sometimes conchoidal. Hardness 3'5 to 4'5 ; scratches calca- 

 reous spar, and U scratched by felspar. Specific gravity 4-63. Opaque ; 



lustre metallic ; colour bronze yellow mixed with red ; streak grayish 

 black. Obeys the magnet but feebly. Soluble in dilute sulphuric acid ; 

 when exposed to the blow-pipe on charcoal is converted into oxide of 

 iron. Occurs at Kongsberg in Norway and Andreasberg in the Harz. 

 Analysis by Hatchett : 



Sulphur 36-5 



Iron 63'5 



100 



Massive varieties amorphous, structure foliated, granular, compact. 

 Found in Cornwall, Wales, Germany, North America, &c. 



Iron Pyrites; Martial Pyrites; Persulp/iuret, or Buulphuret of 

 Iron, occurs in attached and imbedded crystals, and massive. 

 Primary form a cube. Cleavage parallel to the primary planes, distinct, 

 less so parallel to the planes of the octohedron. Fracture uneven, 

 sometimes conchoidal. Hardness 6'0 to 6'5 ; scratches felspar, and is 

 scratched by quartz. Colour brass-yellow ; streak brownish-black ; 

 lustre metallic opaque. 



Massive varieties amorphous, structure granular, compact ; globular 

 and stalactitic, structure fibrous or columnar, radiating ; surface fre- 

 quently reddish brown, owing to the loss of sulphur and acquisition 

 of oxygen. It sometimes contains gold ; the pyrites of Anglesey, 

 Sweden, and Bohemia contains selenium. 



By the blow-pipe sulphur is expelled, and magnetic oxide of iron 

 remains. It is scarcely acted upon by dilute sulphuric acid, but nitric 

 acid dissolves iron and deposits sulphur. Analysis by Hatchett : 



Sulphur 52-15 



Iron 47-85 



100 



Iron pyrites occurs abundantly in every part of the world. It is 

 frequently found in the form of various fruits. The amorphous 

 occurs sometimes to a great extent in coal-beds. Very large crystals 

 occur in Cornwall and South America. The massive varieties in 

 general more readily become oxidised and converted into sulphate of 

 iron than the crystallised, and hence it is largely employed in preparing 

 copperas. The sulphurets are not used for obtaining iron on account 

 of the difficulty of separating the sulphur. The bisulphuret is princi- 

 pally used for procuring sulphate of iron, sulphuric acid, and sulphur. 

 It is also used in preparing alum. 



White Iron Pyrites occurs in attached crystals and massive. Primary 

 form a right rhombic prism. Cleavage parallel to the planes of the 

 primary form. Fracture uneven, granular. Harduess 6'0 to 6'5; scratches 

 felspar, is scratched by quartz. Colour various shades of yellowish, 

 greenish, and gray ish- white ; streak grayish-black; opaque; lustre 

 metallic. 



Massive varieties botryoidal, reniform, stalactitic, and amorphous. 

 Structure diverging, fibrous, or columnar. It is found in Cornwall, 

 Derbyshire, Bohemia, and various other mining districts. According 

 to Berzelius it consists of 



Sulphur . 53-35 



Iron 45-07 



Manganese 0'70 



Silica 0-80 



99-92 



Arsenical Iron Pryrilet, or ititpickel, consists of a mixture of iron, 

 arsenic, and sulphur. It occurs in rhombic prisms, with cleavage 

 parallel to the faces. The colour is silver-white ; streak dark grayish- 

 black ; lustre shining. A cobaltic variety contains 4 to 9 per ceut. of 

 cobalt in place of a part of the iron. Mispickel is found mostly 

 amongst primitive rocks, and is commonly associated with ores of 

 lead, silver, iron, or copper. It is abundant at Freiburg and Muuzig, 

 on the continent of Europe, and in Cornwall in England. It is also 

 found in the United States in many places. Leucopyrite is an arsenical 

 iron without sulphur, found in Styria, Silesia, Carinthia, and the 

 United States. 



Chromate of Iron is a compound of chromic acid, protoxide of iron, 

 and alumina and magnesia. [CHROMIUM.] It occurs usually in 

 serpentine rocks, in imbedded masses or veins. 



Colwnbite is a native columbate of the oxide of iron. [CoLUMBiTE.] 



Wolfram is a combination of iron, tungsten, and manganese. 

 [TUNGSTEN.] 



Oreen Copperas, or Green Vitriol, is a sulphate of iron. It crystallises 

 in the form of acute oblique rhombic prisms, but generally occurs 

 pulverulent or massive. The colour is greenish to white ; lustre 

 vitreous. Taste astringent, sweetish, and metallic. It is brittle, and has 

 a hardness of 2. The specific gravity is 1'83. It becomes magnetic 

 before the blow-pipe. It yields a green glass when fused, and gives a 

 black colour with gallic acid. By exposure it becomes covered with 

 a yellowish powder, which is a persalt of iron. Green vitriol occurs as 

 the result of the decomposition of iron pyrites. The old mine of 

 Rammelsberg in the Harz near Goslar is its most noted locality, but 

 it is found wherever pyrites is exposed to the air. 



Coquimbite, or White Copperas, and Yellow Copperas, are names of 

 two sulphates of the peroxide of iron. Pi/tzite and Fibro-femte are 

 allied compounds. Apatelite is another containing but 4 per cent, of 

 water. 



VoUaite is a double sulphate of iron, alumina, potash, and water, 

 crystallising like alum in octahedrons. It occurs at the Salfatara near 

 Naples. 



