Occurrence of Jade in British Columbia. 367 



Sockets for fire-drills (both from Alaska) 2 



Mallets (both from Alaska, and probably pectolite) ... 2 



Fragments 2 



Spear head (?) 1 



Burnisher or whetstone (from Alaska, and probably 



pectolite) ' 1 



Pendant (from Alaska, and probably pectolite) 1 



61 

 Of the above specimens, sixty-one in number, seventeen 

 show evidence, more or less distinct, of having been sawn 

 in the manner subsequently noticed. 



The chemical composition of jade is such as to show that 

 it can scarcely be supposed to have originated from the 

 usual materials of sedimentary rocks* by ordinary pro- 

 cesses of metamorphism. The origin of a mineral of this 

 kind must be sought among rocks immediately or proxim- 

 ately of eruptive origin, in connection with certain classes 

 of which (as, for instance, minerals of the pyroxene group) 

 it may reasonably be supposed to have arisen as an altera- 

 tion product. This view appears to be borne out by an 

 examination~of the suites of specimens of which those here 

 classed as jade form a part. Some of these specimens are 

 perfectly homogenous and structureless to the eye, consist- 

 ing apparently of pure translucent jade. Others are 

 clouded or variegated in colour, more opaque, and becom- 

 ing in some instances distinctly laminated. A few exhibit 

 on polished surfaces, at right angles to the planes of lami- 

 nation, a minutely lenticular structure, as though granules 

 varying in composition or colour had been welded together 

 by pressure acting in a single direction, in the manner fre- 

 quently observed in fragmental volcanic rocks. One or two 

 specimens, which though apparently forming terms of the 

 same series with the jades, can scarcely be classed as such, 

 are pretty evidently of fragmental origin, and have the 

 appearance of altered volcanic ashes or sand. None of the 

 examples show any definite evidence of having been vein- 

 stones. 



If it be admitted that jade has resulted from the alteration 



* It seems reasonable to exclude from this class certain rocks 

 occurring among the older crystalline schists, the material of which 

 has very possibly been originally volcanic. 



