OF CENTRAL CANADA PART II. 



129 



other altered rocks of the metamorphic country south of the St. Law- 

 rence, as in the townships of Leeds, Halifax, Inverness, Hani, Shipton, 

 Cleveland, Stukely, Bolton, Brome, Sutton, &c. 



96. Azurite or Blue Carbonate of Copper : This species has hither- 

 to been recognized only in small incrustations and stains of a blue 

 colour, associated with malachite, at most of the localities named 

 under No. 95, above. The blue carbonate contains : carbonic acid 

 25.6, oxide of copper 69.2, water 5.2. 



K. SULPHATES. 



[The mineral substances placed under this division may be regarded, 

 according to the commonly received view, as compounds of sulphuric 

 acid with one or more oxidized bases, such as baryta, lime, oxide of 

 lead, alumina, and the like. As regards physical characters, these 

 bodies exhibit a non-metallic aspect, and either a colourless or a very 

 faintly-coloured streak, the colour in the latter case being green or 

 blue, or occasionally yellow. They afford representatives of all the 

 systems of crystallization : Rhombic and Clino-Rhombic types being 

 especially abundant. H = 1.0 4.0. The sulphates may be easily 

 distinguished from carbonates, phosphates, silicates, &c., by fusion in 

 a reducing flame on charcoal with carb-soda ; or better with a mixture 

 of carb-soda and a little borax, as the latter reagent facilitates the 

 decomposition of earthy sulphates, and prevents the absorption of the 

 fused mass. An alkaline sulphide is formed by this treatment. 

 When moistened, and placed on a piece of silver or on lead test-paper 

 (a bright coin or glazed visiting card may be used as a substitute), 

 the fused mass produces a black or brown stain of sulphide of silver 

 or sulphide of lead. The stain may be easily removed from the silver 

 by friction with moist bone-ash. 



Amongst the sulphates generally, several natural groups stand out 

 with great prominence. The Rhombic group of anhydrous species, 

 for example, containing the Sulphates of Baryta, Strontia, Lime, 

 Lead, &c. ; the Gypsum group ; the Monometric group of Alums ; 

 the Prismatic group of Vitriols ; and others of subordinate impor- 

 tance. The sulphates hitherto found in Canada, are too few, however, 

 to admit of distribution into special groups of this kind. In the 

 descriptions which follow, the anhydrous species Barytine and Celes- 

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