522 A POPULAR EXPOSITION OF THE 
Topaz.—Chiefly in yellow, colourless, or bluish crystals and rolled pebbles, 
easily distinguished from quartz by their faeile cleavage in one direction. The 
erystals are combinations of rhombie prisms and pyramids (see figs. 16 and 18 in 
Part I.) H. 8-0; sp. gr. 3:4-3°6. In the United States, Topaz occurs in Connec- 
ticut and North Carolina. 
Tin-stone or Casstterite.—Brown, grey, black, ete. In granular masses, pebbles, 
and Dimetric erystals, the latter often in twin combinations, Very hard and very 
heavy, (H. 6:0-7:0; sp. gr. 6°3-7:0.} Infusible, but yielding tin globules before 
the blowpipe, especially with carbonate of soda. The lustre isoften semi-metallic. 
This is the “ ore” of tin, properly so-called. One hundred parts consist of: oxygem 
21°38, tin 78°62. In the United States it occurs but sparingly, and no traces of it 
have as yet been found in any part of Canada. 
C. 2. Infusible. Yielding easily to the knife. 
Cyanite.—Chiefly in lameliar and bladed or broad—fibrons massez 
of a pale-blue, or pearl-grey colour, though often white, reddish, &e. 
Lustre somewhat pearly. The edges of the lamelle seratch glass 
with ease, whilst the flat surfaces yield readily to the knife. Sp. er. 
3°5-3°7. Infisible before the blowpipe, and very slowly soluble in 
borax. One hundred parts consist of: silica 37, alumina 63. Not 
met with, apparently, in Canada, but it oceursin mica slate im 
Vermont, and is of frequent occurrence in other States. 
Apatite or Phosphate of Lime :—Chiefly m six-sided prisms (oftem 
with rounded edges) of a light green colour; or in green and brown- 
ish cleavable and concretionary masses. H. 5-0; sp. gr. 3:0-3°3. 
Infusible (or in some specimens fusible with difficulty on the thinnest 
edges), but it dissolves readily in borax and in salt of phosphorus, 
yielding a glass which becomes opaque on cooling er when “ flamed.” 
By this character, as well as by its inferior hardness (as 16 scratches 
glass but feebly, and may readily be scratched by a kmfe,) Apatite 
is easily distinguished from green feldspar and beryl. Tt differs from 
Fluor Spar in being hard enough to scratch glass : also by its infusi- 
bility, crystalline form, &c. Apatite occurs in the erystalline lime- 
stones of our Laurentian rocks. Amongst its more important 
localities, we may cite the townships of Burgess and Elmsley, in 
Canada West; with Grand Calumet Island on the Ottawa, and Hull 
township, in Eastern Canada. In the township of Burgess it oecurs 
in a red-coloured coarse-grained limestone in such abundance as to 
form, according to the estimate of Sir Wiliam Logan, about one- 
third of the mass. In North Elmsley, a fine locality has recently 
been discovered by Dr. James Wilson, of Perth. Small nodular 
