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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 143 



amounts of o.oi percent or less are included in this list. The analyti- 

 cal procedure used has been described in detail by Waring and Annell 



(1953)- 

 The chemical analyses of both specimens are essentially the same 



(table 4). The analysis reported here for the Martha's Vineyard 



tektite also agrees equally well with the independent analysis of a 



different part of the same specimen given by Kaye et al. (1961). 



Table 4. — Chemical analyses of the Georgia and Martha's Vineyard tektites 



Martha's Vineyard 

 Georgia tektite * tektite b 



Elemental oxide percent percent 



SiOa 80.54 80.6 



AlaOs 11.21 II.3 



FeaOa O.33 0.4 



FeO 2.40 2.2 



CaO 0.61 0.7 



MgO 0.65 0.7 



MnO 0.05 0.05 



Na a O 1.16 1.1 



KaO 2.38° 2.4 



H a O" None <o.i 



H a O + 0.02 <o.i 



TiOa 0.43 0.5 



Total 99-78 99.9 



» Analyst: M. K. Carron, U. S. Geological Survey. 

 b Analyst: R. S. Clarke, Jr., Smithsonian Institution. 

 c Analyst: W. W. Brannock, U. S. Geological Survey. 



A gravimetric chloride determination was also done on a small 

 sample of the Georgia tektite. The figure of 0.03 percent chloride 

 obtained represents a limiting value. Chloride could not be present in 

 a concentration greater than this, but the true value could be consider- 

 ably less. The analysis of the Martha's Vineyard specimen is reported 

 to only one decimal place because of the small size of sample used for 

 analysis. 



The chemical data on the Georgia and Martha's Vineyard glasses 

 (table 4) fit quite well into the general pattern of tektite analyses as 

 presented by Barnes (1940) in his review of this subject. The high 

 silica, high alumina, high ferrous to ferric iron ratio, and the excess 

 of potassium oxide over sodium oxide are all typical of tektite 

 analyses. The moldavites are the only tektite group that have silica 

 contents as high as those obtained in our analyses, and moldavites 

 are the group most similar in physical and morphological character 

 to our material. It is of interest to compare Barnes's moldavite 



