120 MINERALS AND GEOLOGY 



particles which become lustrous when rubbed, occurs in Madoc and 

 elsewhere in the counties of Hastings and Peterborough, and prob- 

 ably in other parts of that region. Finally, it may be observed that 

 many of the metamorphic slates of the Eastern Townships appear to 

 owe their nacreous talcose aspect the presence of kaolinite, or to that 

 of the related non-magnesian silicates described under Finite, below. 



85. Finite (including Aluminous- Agalmatolite and Parophite, &c.): 

 Greenish or greyish-white, dull-yellow, grey, green, brown, &c. In 

 compact, granular, and sometimes slaty masses : also occasionally in 

 pseudomorphous crystals. Very sectile, and more or less unctuous to 

 the touch. H = 2.5 to 3.5 ; sp. gr. 2.65 2.8. BB, infusible, or 

 fusible with difficulty on the edges only. The light-coloured varieties 

 assume a blue tint after ignition with nitrate of cobalt, In the bulb- 

 tube, yields water. More or less attacked by acids. Average com- 

 position : silica 45 to 55, alumina 25 to 35, iron oxides 1 to 4, potash 

 6 to 10, with small amounts of magnesia, soda, &c., and from 5 to 8 

 per cent, of water. 



The term Finite (from the Fini mine near Schneeberg in Saxony) 

 was originally restricted to certain brown pseudomorphous crystals 

 apparently derived from the decomposition of lolite, but it is now 

 applied by Dana so as to include a number of related substances of 

 various colours and modes of occurrence. These substances are essen- 

 tially hydrated silicates of alumina and potash, much resembling the 

 magnesian steatites and serpentines in their physical characters. One 

 of the best known is the Chinese Agalmatolite or Figure-stone, but 

 many of the so-called agalmatolites are magnesian in composition, and 

 identical with steatite. Dr. Hunt refers the Wilsonite (see No. 63 > 

 above) to this group, on account of its composition ; but its physical 

 characters are quite distinct from those of the typical pinites and agal- 

 matolites. It wants the sectility and soapy feel, for example, so char- 

 acteristic of these latter, whilst it possesses, on the other hand, a dis- 

 tinctly spathoid structure. 



The agalmatolite variety occurs in beds and layers amongst the 

 strata of the Eastern Townships of Canada, especially in St. Nicholas 

 (LeVis), where it forms green and greenish- white layers in an indura- 

 ted clay-slate of the Quebec group (see Part V.) ; also near St. Francis- 

 (Beauce), in yellow, waxy-looking, semi-translucent layers ; and on 

 Lake Memphramagog in Stanstead, where it occurs in yellowish 



