742 



DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



TABLE XL VIII. 



Specific gravities of rocks and (/lasses. 



Authority. 



Delesse 



Cossa . . 

 Cossa . . 



Delesse 



Delesse 

 Delesse 



Rock type. 



Spec. grav. 

 of rock. 



Granite . 



Syenite 



Quartz dioritc . 



Diorite 



Gabbros . 

 Gneiss . . 



730 

 623 

 684 

 680 

 751 

 700 

 660 

 643 

 710 

 667 

 921 

 799 

 858 

 100 

 898 

 821 



Spec. grav. 

 of glass. 



•4"0 

 ■360 

 •423 

 ■427 



496 

 ■447 

 ■425 

 ■478 

 •430 

 •403 

 ■679 

 •608 



684 

 ■664 

 •641 

 •625 



Net decrease 

 in density. 



■26% 



03 

 •72 

 •44 

 ■27 

 •37 



84 

 •24 



33 

 •90 

 ■29 

 •82 



09 



06 

 •87 

 •95 



TABLE XLIX. 



Specific gravities of crystals and glasses. 



Artificial anorthite 



ii albite 



Purified natural quartz 



Artificial orthorhombic amphibole 



H ti pyroxene , 



ii monoclini 3 pyroxene. .. . 



ii diopside 



Average of all seven 



Spec. 



grav. 



of crystal. 



2-765 



2 



605 



2 



654 



2 



857^ 



3 



175 V 



3 



192 J 



3 



275 



Spec. grav. 

 of glass. 



2 700 

 2-382 

 2-213 



2 743 



2 830 



Decrease 

 in density. 



2-4% 



85 

 16 6 



40 

 13 6 

 14- 1 

 136 

 10 6 



