Vol. 5] 



Louderback. — Ben itoii e. 



375 



Nept u niter 7 W. M. Bradley has recently published the fol- 

 lowing analyses of the San Benito neptunite 28 with values very 

 close to those given by Blasdale. 



Bradley Blasdale 



I II Mean Mol. Ratios Mean Mol. Ratios 



Si0 2 52.91 52.83 52.87 .875 53.44 .820 



TiO. 17.77 17.89 17.82 .222 17.18 .213 



FeO 11.54 11.83 11.69 1 11.23 1 



MnO 0.82 0.88 0.85 ! 2 35 1-78 ! 



CaO 1.59 1.53 1.56 j " 0.25 [ - 230 



MgO 1.41 1.48 1.44 J 1.82 J 



K = 5.11 5.06 5.08 i OQ8 5.39 1 OQ4 



Na 2 9.83 9.28 9.56 f ' 9.14 J ' 



100.98 100.78 100.88 100.23 



Albite. A recent abstract in the Zeitschrift fiir Krystallogra- 

 phie 29 shows that Dreyer and Goldschmidt have studied some 

 remarkably form-rich albites from Greenland, in which are found 

 among others certain of the rare forms and the supposedly new 

 form on the San Benito albite: u (221 )=u ( 221) (S.B.) ; a(l20) 

 ==,,(120) (S.B.. following Klockmann) ; ij (131)==® (131) (S.B.). 

 It may be noted that the angles for the San Benito albite reported 

 by the writer agree more closely with the values calculated by 

 Dreyer and Goldschmidt from their newly determined elements, 

 than they do with the angles calculated from the Brezina elements 

 given above (p. 362). 



Measured Calculated 

 San Benito Albite (Elements ot Dreyer & Goldschmidt) 



P(001) 



81° 



56' 



26° 



50' 



81° 



59 



26° 



51' 



1(110) 



60 



27 



90 



00 



60 



38 



90 



00 



T(1T0) 



119 



54 



90 



00 



120 



04 



90 



00 



i;(lS0) 



138 



47 



90 



00 



138 



59 



90 



00 



/'(130) 



30 



16 



90 



00 



30 



24 



90 



00 



3(130) 



149 



47 



90 



00 



149 



50 



90 



00 



ar(TOl) 



80 



50 



25 



58 



80 



44 



26 



00 



e(lll) 



108 



28 



57 



35 



108 



34 



57 



26 



o(TTl) 



T35 



26 



34 



07 



T35 



Q 



34 



16 



5(TT2) 



177 



00 



11 



42 



177 



14 



11 



39 



®(I51) 



T63 



19 



59 



13 



T63 



17 



59 



8 



27 A German translation of Ford's paper on neptunite cited above 

 occurs in Zcit. fiir Eryst. u. Min., 46 (1909), pp. 321-325. 



28 Am. Jour. Set. (4), 28 (1909), pp. 15-16. Also German translation 

 of the same, Zcit. fur Kryst. u. Min., 46 (1909), pp. 516-517. 



-'< liber Albit von Gronland: Meddelelser am Gronland, 34 (1907), 1-60. 

 Ref. Zeit. fur Kryst. u. Min., 46 (1909), p. 605. 



