134 MINERALS AND GEOLOGY 



acid 28.5, oxide of nickel 26.7, water 44.8. Detected by Dr. Steriy 

 Hunt, as an efflorescence on an aresenical nickel ore from the Wallace 

 Mine, Lake Huron. (See No. 17, above.) 



103. Alum: Normally, white, but sometimes stained of a yel- 

 lowish or brownish colour by sesquioxide of iron and other impurities. 

 Monometric in crystallization, but occurring commonly in earthy 

 efflorescent crusts. Soluble : taste, sharp and more or less bitter. 

 BB, froths up and forms a white earthy mass which assumes a fine 

 blue colour if moistened with a drop of nitrate of cobalt, and again 

 ignited. Normal composition : sulphuric acid 33.75, alumina 10. 82, 

 potash 9.95, water 45.48. Occurs in considerable abundance on the 

 exposed face of some high bluffs of argillaceous shale (belonging to 

 the Animikie series) on Slate River, a tributary of the Kaministiquia,, 

 about twelve miles west of Fort William, Lake Superior. 



L. PHOSPHATES AND ARSENIATES. 



[These compounds are composed of phosphoric acid or arsenic acid 

 with various bases. They present a vitreous or other non-metallia 

 aspect. Phosphates when moistened with a drop of sulphuric acid 

 (and many without this addition), impart a green colour to the point 

 of the blowpipe flame. When fused, in powder, with carb. soda in, 

 a platinum spoon, an alkaline phosphate is formed, soluble in water. 

 The clear solution decanted from the insoluble residuum, and acidified 

 by a few drops of nitric acid, yields a canary yellow precipitate with 

 a drop or two (or small fragment) of ammonium molybdate. 

 Arseniates, when mixed in powder with some carb. soda, and ignited 

 on charcoal in a reducing flame, emit a very distinct odour of garlic^ 

 Canadian examples, of this group, amount to only three in number, 

 as riven below ; but, one of these, the lime fluor-phosphate. Apatite* 

 occurs in comparative abundance, and is a substance of great com- 

 mercial value.] 



104. Apatite (Phosphate of Lime) : Green, blueish-green, vioJet- 

 red, rose-red, brownish, greenish- white, &c. shades of green and 

 dull-red being often present in the same specimen. Lustre, vitreous 

 and vitreo-resinous, with frequently a slight opalescence on one of 

 the cleavage planes: Crystalliza ion, Hexagonal : the crystals con- 

 sisting most commonly of six-sided prisms, often of large size, and 



