150 CARNEGIE INSTITUTION OF WASHINGTON. 



(26) Aventurine labradorite from California. Olaf Andersen. Amer. Mineralogist, 

 2, 91 (1917). 



In the course of the work on aventurine feldspars (Am. J. Sci. (4), 40, 351, 

 1915; reviewed in Year Book No. 14, p. 169), many specimens in the collection 

 of the U. S. National Museum were studied. One of these, comprising a 

 nimiber of pebbles and six cut stones, from Modoc County, California, proved 

 to be so different from the majority of the specimens that it was not described 

 in the paper above cited. Being practically colorless and transparent, except 

 for the inclusions which yield the red aventurine effect, the identity of the 

 feldspar seemed worth establishing by optical and crystallographic measure- 

 ments. The results are presented in this paper. 



