IRON 



921 



Htematite; Specular Iron; Fcr oligist'e; Micaceous Iron Ore. This ore has a 

 metallic lustre ; colour, iron black to steel grey, but often tarnished ; the light trans- 

 mitted through the thin edges of its crystals appears of a beautiful red colour. Its 

 powder is always of a well-marked brown-red hue, passing into cherry red, which 

 distinguishes it from the black oxide ore ; its fracture is conchoidal or uneven ; it is 

 brittle, and its specific gravity is 5'2. Its chemical composition is Fe 2 s , or 70'03 iron, 

 and 29-97 oxygen ; in the reducing flame of the blowpipe, it becomes black and mag- 

 netic. 



Specular iron includes specimens of a perfect' metallic lustre. The specular variety 

 occurs chiefly in crystalline rocks in large beds or veins. The mines of the island 

 of Elba, celebrated from antiquity, still furnish the finest crystals, which occur in 

 druses of the massive variety, along with pyrites and quartz ; fine crystals are like- 

 wise produced from St. Gotthard, Franiont, in the Vosges mountains, the Hartz, 

 Altenberg in Sweden, and from Katharineriburg in the Ural. 



Micaceous iron ore is that variety of haematite which has a distinctly micaceous 

 character. Beautiful specimens of the micaceous variety occur at Zorge and other 

 parts of the Hartz. At Hennock, not far from Haytor on Dartmoor, a very large lode 

 of the micaceous ore exists ; it is also found near Tavistock in Devonshire, at Huel 

 Owles tin mine, and Botallack tin and copper mine at St. Just in Cornwall, and in 

 Wales, Cumberland, and Perthshire. It also occurs in volcanic rocks, as in Auvergne, 

 on Vesuvius, ^Etna, and the Lipari Islands, especially Stromboli, where some fine 

 crystals, three inches broad and four long, have been procured. 



H&matite is a term more strictly applied to the red varieties of the specular iron 

 ores, on account of the red colour of its powder, from cu/ta, blood. The red haematites 

 are those which have a distinctly red colour when scratched, or which yield a red 

 streak. One variety is known as fibrous red iron. If soft and earthy, it is called red 

 ochre ; a peculiar variety of this kind is found near Rotherham in Yorkshire, and is 

 known as raddle. It is used for polishing lenses in Sheffield, and largely employed for 

 marking sheep. The red chalk used for drawing is a variety of the -same kind. 



Red hcematite. This ore is found in the greatest abundance in- the mountain or 

 carboniferous limestone formations. The- most abundant ^deposits in this country are 

 those of Lancashire and Cumberland. ..... 



The haematite of Whitehaven occurs in the carboniferous limestones near the out- 

 crop or surface-edge of the slaty rocks upon which that formation rests. The greater 

 part of the excavations from which it is extracted are subterraneous, and so extensive 

 is often the mass of iron ore in which the- workings are carried on, that it is difficult in 

 such situations to obtain a clear idea of the nature of this important deposit. ( War- 

 ing ton Smyth.) 



The following are the quantities of red haematite produced since 1868 : 



