306 THE CANADIAN NATURALIST. [Vol. ix. 



T. Under II is given Dr. Hunt's analysis of the chrome-garnet 



from Orford in the Eastern Townships, while, under III, is an 



analysis by Erdmann of the true ouvarovite : 



I. * II. III. 



Silica 37.50 36.65 36.93 



Alumina 18.65 17.50 5.68 



Ferric oxide 1.07 1.96 



Ferrous oxide 4.97 



Chromium sesquioxide . 4.95 6.20 21.84 



Lime 36.13 33.20 31.63 



Magnesia 0.52 0.81 1.54 



Cupric oxide trace. 



Loss on ignition 0.48 0.30 



99.30 99.63 99.58 



On comparing these analyses we see that while in the true 

 ouvarovite, the predominant sesquioxide obtained on analysis is 

 that of chromium, it is alumina in the garnet of Wakefield and 

 Orford. Strictly speaking, therefore, the two last should be 

 classed as lime-alumina rather than lime-chrome garnets. 



The hardness of the Wakefield mineral is a little above 7 and 

 the specific gravity 3.542. Before the blow-pipe it fuses between 

 4 and 5. Notwithstanding that it contains less chromium, the 

 green in the specimens which I have seen is deeper than that of 

 the Orford mineral and quite as deep as that of ouvarovite. The 

 crystals are rhombic dodecahedrons with the faces often striated 

 in the direction of the longer diagonal. In my specimens the 

 well-defined crystals are mostly one-eighth of an inch or a little 

 more in diameter ; but one — unfortunately not entire — is nearly 

 half an inch. On weathering, the crystals lose their glassy lustre, 

 becoming dull and paler in colour. Among the minerals asso- 

 ciated with the garnet are a green pyroxene, which is probably 

 chromiferous, apatite, calcite, orthoclase, tourmaline and idocrase. 



I am greatly indebted to Mr. J. 0. Miller of East Templeton 

 for the specimens which have enabled me to make the above 

 analysis. 



* The Atomic and quantivalent ratios are as follows : 



Atomic. Quantivalent. 



Si 625X4 2500 2500 



AI 362X3 1086") 



Fe 013X3 39}- 1320 



Cr 065X3 195 J | 2636 



Ca 645X2 1290 ^ 



013X2 '26 



} 



