116 ASBESTOS. 



These veins are irregular in thickness and follow no regular 

 course, and terminate often abruptly, pinch out or join other 

 veins ; but as a rule are roughly parallel to one another. In 

 Italy the quantity and quality are stated to vary according to 

 the direction of the rock surface, being good and abundant 

 when facing southerly and westerly, good but scarce when facing 

 eastward, but of bad quality when the rock faces towards the 

 north. In Canada the quality and quantity seem to depend 

 upon proximity to certain eruptive dykes, and the same feature 

 as regards quantity seems to obtain in Queensland. The 

 chrysotile fibres occur always at right angles to the sides of the 

 fissures, and are often accompanied by long brittle fibres of an 

 allied mineral known as picrolite, whose fibres run in a contrary 

 direction, viz, parallel to the sides of the fissure. Mica, talc, 

 and certain rare minerals are found also with it, and in Canada 

 granules of chrome iron ore are said to be an invariable 

 accompaniment. 



The great serpentine belt passing through the eastern 

 townships of Quebec is traversed by masses of dioritic or doleri- 

 tic rocks, of which it is supposed by some to be an alteration 

 product. The serpentine is frequently associated with dykes of 

 whitish rocks composed of quartz and felspar, at times forming 

 a granitoid rock known as granulite, the presence of which have a 

 marked influence upon the quantity and quality of the asbestos. 

 The veins at the surface are discoloured and decomposed, render- 

 ing the mineral of small value, and where the rock is much 

 shattered this is more noticeable, but at a depth the quantity and 

 quality of the fibre increase, and this increase is an established 

 fact in all the mines. The veins have the character of true 

 segregation veins, and the contaming walls are often changed in 

 character for a distance of ^ to 3 inches at each side. The 

 mineral is rather quarried than mined, and is blasted out from 

 large open cuts, broken and cobbed by hand, and sorted into 

 three qualities according to length and quality of the fibre. 

 The long fibres are often discoloured, and the bulk of the mineral 

 sent into commerce is obtained from veins varying from f of an 

 inch to 2J inches wide, and these are numerous in all the mines 

 and of excellent quality. The marketable mineral forms about 

 5 per cent, of the total rock broken down, and of this about one- 



