CLASSIFICATION OF IGNEOUS ROCKS 



655 



TABLE II. 



HESSOSE (AMPHIBOLE GABBRo) BEAVER CREEK, BIG TREES QUAD- 

 RANGLE, CAL. 



A. J. S., Vol. VIII (1899), p. 297; Bull., 168, U. S. G. S., p. 206. 



Si0 2 



Al a O. 



Fe 2 G\ 



FeO . 



MgO 



CaO. 



Na„0 



K 8 



H 3 0+ 



H s O— 



Ti0 2 . 



p 3 o 5 . 



CI... 

 Cr 2 

 MnO 

 SrO . 

 V 8 O a 

 FeS 



Per Cent. Mol. Apat. Ilm. Mag. Orth. Alb. An. Diop. ^ em ' Hyp. Oliv 



47.27 



20.82 



1.85 



4.26 



6.44 



13.02 



^•75 

 .22 



1 .27 

 .08 

 .92 



•74 

 tr 

 tr 

 tr 

 tr 

 .02 

 .20 



99-86 



204 

 on 



059 

 161 



232 

 044 

 002 



on 



005 



12 264 



2 44 



44 



306 

 158 



15S 



118 



59 

 59 



139 



37 



37 



5i 



-r + 



y . 



88 SiO„ 



FORMULA. 



K 2 O.Al,0 3 .6Si0 2 



Na„O.A"l 2 3 .6SiO„ 



Ca6.A],0„.2SiOo" 



CaO.SiOo" 



MgO.SiOo 



FeO.SiO., 



MgO Si0 2 - 

 FeO.Si0 2 



2MgO.SiO„ 

 2FeO.SiO„" - 

 FeO.Fe 2 0" 3 - 

 FeO.TiO, 

 3 CaO.P 2 - 

 FeS, 



x + y — 139 (Mg, Fe) O 

 y = 102 

 -*•= 37 



MOL. WT. 



2 X 556 



44 X 524 

 158 X 278 

 59 X 116 • 

 48 X 100 . 

 11 X 32 • 



30 X 100 1 

 7 X 132 1 



83 X 70 1 



19 X I02 < 



11 X 232 



11 X 152 

 5 X 310 



orthoclase 



albite 



anorthite 



= hypersthene = 



= olivine 



= magnetite 

 = ilmenite 

 = apatite 



pyrite 



etc. 



1. 11 

 23.06 J 

 43-92- 



= diopside = 13.10"! 



1- P + O 



= 2 



= 1 



7Sj 



6 7 i M 



55 A 

 20 ) 



37 



.09 Sal 68.09 



Fern 30.74 



CLASS II. 



Sal _ 68.09 ^7^5 



Fem 30.74 1 3 



Dosalane. 



order s 



Gertnanare. 



rang 4. 



_ 68.09 -^ 7 K 2 0'+Na 2 Q' 46 3 1 

 o 'i CaO' ~ 158^5^7 



Hessose. 



