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PEOCEEDINGS OF THE NATIONAL MUSEUM 



Analysis of yellow garnet 

 [L. G. Eakins, analyst] 



VOL. 71 



The ratios of this analysis do not approach so nearly to the ideal 

 garnet proportions, the high bases and silica as well as the presence 

 of magnesia and soda suggesting contamination of the sample by 

 some foreign constituent which seems surprising, as the material of 

 the specimens appears ideal. This also is essentially a simple mem- 

 ber of the andradite-grossularite series, but here andradite makes 

 up a greater proportion, the analysis indicating approximately 60 

 per cent of andradite to 40 per cent of grossularite. The specific 

 gravity of a garnet of this composition should be 3.662, while the 

 specific gravity of the analyzed sample is recorded as 3.72 at 16° C. 

 The refractive index should be 1.831. It was found to be well above 

 1.80, the highest immersion oil at hand. 



One other garnet analysis made on material from this localitj'^ is 

 recorded by Eakins. This gives the following results : 



Analysis of garnet 

 [L. Q. Eakins, analyst] 



This appears to be a much better garnet analysis than the last, but 

 there is nothing to indicate the type of material or the specimen on 

 which it was made. It evidently is also a member of the andradite- 

 grossularite series, containing 55 per cent andradiate and 45 per cent 



