OF CENTRAL CANADA PART II. 137 



104. Vivianite (Hydrated Phosphate of Iron) : Blue, bluish-green 

 (normally, colourless, but becomes blue on exposure) ; streak pale- 

 blue or blueish-white. Monoclinic in crystallization, with very per- 

 fect cleavage in one direction, but found more commonly in bladed 

 and fibrous varieties, and in earthy masses, often forming, when in 

 the latter condition, beds or layers of a certain extent. H = 1.0 

 2.0; sp. gr. 2.55 2.7. BB, tinges the flame-point pale-green (from 

 presence of phosphoric acid), and yields a dark magnetic globule. In 

 the bulb-tube gives off a large amount of water. Normal composi- 

 tion : phosphoric acid 28.30, iron protoxide 43.00, water 28.70, but 

 the iron in the coloured varieties is always partly in the state of 

 sesquioxide, and the earthy varieties moreover are usually mixed 

 with a certain amount of clay, sand, iron ochres, manganese ochre, 

 or other foreign matters. In Canada, this mineral has only been 

 found in an earthy condition, underlying a bed of bog iron ore, in 

 Vaudreui], on the Lower Ottawa. 



105. Cobalt Bloom (Erythrine, Arseniate of Cobalt) : Occurs 

 only (as regards Canada) in the form of a slight efflorescence or in- 

 crustation, of a peach-blossom red colour, on the silver-holding calc 

 spar of Prince's Location, on the north-west shore of Lake Superior ; 

 and also, but in traces only, in the more recently discovered silver 

 bearing vein near Thunder Cape. Normal composition : arsenic acid 

 38.25, oxide of cobalt 37.85, water 23.90 ; but sometimes mixed 

 with arsemous acid. 



IV. FLUORIDES AND CHLORIDES. 



[This subdivision comprises the compounds of Fluorine and Chlo- 

 rine, respectively, with metallic bases, such as sodium, calcium, alu- 

 minum, lead, silver, and the like. These compounds present a non- 

 metallic aspect ; and they exhibit a general resemblance, also, in 

 other characters, to many so-called oxygen salts, more especially to 

 certain phosphates, borates, carbonates, and sulphates. Amongst 

 Canadian minerals, however, as at present discovered, we have but a 

 single representative of each group.] 



A. FLUORIDES. 



[The only Fluoride as yet discovered in Canada, is the fluoride of 

 calcium, long known under its popular name of Fluor Spar. In a 

 strictly natural classification, this mineral should occupy a place in 



