1907-1908.] 85 



"COLOURS and superficial appearances of flint 



IMPLEMENTS." 



Mr. Strachan, in his remarks, observed that fresh flint, the 

 material from which flint implements were made, is a dark-coloured 

 compact variety of silica. It is amorphous in appearance, and is 

 nearly related mineralogically to quartz. It is somewhat lighter, 

 however, than the latter, and this fact is usually accounted for by 

 the supposed presence in flint of a small proportion (15 to 20 per 

 cent.) of light opaline silica. The latter is a more soluble form 

 of silica than quartz, and certain it is that a variable proportion 

 of the silica in flint, approximating to the above amount, is more 

 soluble than the bulk. Flint implements sometimes preserve their 

 fresh appearance, but more often are weathered, altered, and 

 stained. The weathering and staining sometimes permeate and 

 penetrate right through the material of the implement, but 

 generally such changes are purely superficial. The colours and 

 superficial appearances of flint implements are caused by alter- 

 ations in the material of the flint, due to external influences and 

 by the infiltration of foreign substances in solution. The general 

 appearance of an implement cannot be depended upon as an 

 index to its age, except in very occasional instances, and even then 

 many points have to be weighed or considered before any reliable 

 conclusion can be arrived at by the collector. 



A spirited discussion followed the reading of these papers, in 

 which Mrs. Hobson, Mr. W. Gray, M.R.I.A., Mr. W. A. Green, 

 Miss Andrews, Mr. A. Milligan, Mr. Carson, and Mr. H. L. Orr 

 took part, and expressed opinions that the Club was to be 

 congratulated on the matters brought forward. 



