>4 



W. T. Schaller- 



—California Minerals. 





No. 



1 



2 



3 



4 



5 



6 



CuO__. 





7-56 



9-17 



10-07 



12-61 



15-52 



FeO . . . 



.. 25-86 



15-85 



16-37 



(16-15) 



14-14 



12-14 



SO,.... 



.. 28-80 



30-74 



29-00 



28*84 



28-44 



27-82 



H o 0__. 



45-34 



45-85 



45-46 



(44-94) 

 '100-00 . 



44-81 

 100-00 



44-52 





100-00 



100-00 



100-00 • 



100-00 



No. 



7 



8 



9 



10 



11 





CuO ... 



.. 15-56 



17-45 



17*64 



18-81 



27-85 





FeO ... 



.. 10-98 



10-18 



9-62 



8-51 



-■-.. 





SO,.... 



.. 29*90 



28 ; 43 



28-27 



27-93 



28-02 





H 2 ... 



, 43-56 



43-94 



44-47 



44-75 



44-13 





100-00 100-00 100-00 100-00 100-00 



Quartz Pseudomorph after Apophyllite. 



At the Datolite and Pectolite* locality near Fort Point, San 

 Francisco, Cal., a small group of crystals was found which 

 were at first taken to be apophyllite. However, as the crystals 

 proved to be infusible, a more extended investigation of the 

 mineral was made. 



The crystals, from one to three mm. in diameter, appear 

 cubic with the corners truncated by small faces. Measurements 

 of the best crystals showed that they are tetragonal and that they 

 agree in angles with those of apophyllite. The forms present 

 are the base, prism of the second order and the unit pyramid 

 of the first order. The prism faces are vertically striated and 

 faces of the other two forms are also rarely somewhat striated. 



By trial it was found that hydrochloric acid does not attack 

 the crystals, so the associated calcite was easily removed and 

 pure material for analysis obtained. The crystals are opaque 

 and no optical determinations could be made. 



The analysis gave the following figures, showing that the 

 crystals are now, chemically, essentially silica with various 

 impurities. 



Si0 2 _. _. 90-58 



A1 2 3 1-58 



CaO 1-87 



MgO 220 



H 2 4-32 



100*55 



* Mineralogical Notes by A. S. Eakle, Bull. Dept. Geol. Univ. Cal. , vol. ii, 

 No. 10. 



Laboratory of the U. S. Geological Survey, November. 



